Using HCl for clearing blood traces

[PyroTech]

Hello,
If someone saw the movie: "Boondock saints", then you probably know the scene, were a guy get shot in the shoulder. Some blood splashes on the balcony, and to prevent that the cops would get his blood/DNA, he has a little spraycan, full with some hydrochloric acid, and he sprays the HCl on the blood. Later in the movie, a FBI agent tells another FBI agent that the blood is useless, because the blood was "destroyed".

I thought this was pretty cool, does anybody know if this really works? Maybe with another acid, like H2SO4.

I made a new tread because I couldn't find anything about this subject, and I thought improvised weapons would be the best section.

[Ghostcustom 24]

It may work if the concentration of the hydrochloric acid is high enough. I wonder if hydrogen peroxide works? (I would bet that would destroy the blood since it kills bacteria, but I am not sure)

I have seen that State Troopers carry 2 two-liter bottles of Coke in their trunks to pour over bloodstains on the highways. They explained it to me saying that in about 15 minutes it eats away at all of the blood. I believed them because I have seen the classic experiment where they dissolve a T-bone steak in Coke.

Anyone know anything about this?

[Keyser Soze]

The Boondock Saints is one of my favorite movies, i believe they are working on a sequel. I also just popped it in and the line Wilem Dafoe says is, "They used ammonia, none of this is any good, FUCK!"

So i think it was ammonia and not HCl. Even if you were to try it, yo might need it in higher concentrations than you get in the grocery store though.

[Ghostcustom 24]

Yes, higher concentrations would probably be the key. Almost any type of acid (that would be able to destroy the DNA) should probably work.
I can have a definite yes or no answer tomorrow.

[PyroTech]

Aha, was it ammonia? I'll watch it again this weekend.

Using coke for eliminating the traces of blood? That is a weird idea!

I think you have a big chance that H2SO4 works too. I guess I could do some simple tests, with HCl (30%) H2O2 (30%) and H2SO4 (>95%), just add a little piece of meat to it. But I wouldn't have a clue, if the DNA is destroyed then.

But if an acid destroys the DNA, wouldn't stomach acid be a little problem? :confused: I guess a nice NaOH solution would do pretty good, reminding that it destroys hair and all filthy stuff in the drain.

But if it was so easy, why wouldn't every dumb criminal use it? Well I guess it's the same thing as always wearing leather gloves.
I also love that movie Keyser, it's such a great script.

[Einsteinium]

There is nothing weird about using coke since it contains phosphoric acid in good amount (Coke's ph ~1,5-2,5). Strong acids catalyzes hydrolysis of DNA, cleaving it into fragments (this includes HCl, H2SO4, H3PO4, HNO3, HBr...). Strong bases also catalyze hydrolysis of DNA but I've never heard of any cases where it was used. Strong oxidants such as KMnO4 and hypochlorite (bleach.. pool chlorine) solutions does destroys DNA very conviently, and this is quite frequently used (bleach) by criminals to destroy evidence.

BTW, forensic chemist are still able to determine if there were blood and/or blood fragments on a scene even if you did your best to destroy it. They just won't be able to analyze it and relate it to somebody.

[photonic]

I think you're mistaken. Ammonia is what they said was in the can. Good movie, btw. I'm fairly certain HCL would definately complicate things, but forensics techniques seem to be pretty advanced these days(still I think like > 3/4 of murders go unsolved). Are there any forensics book in the "Library"?

Edit: I typed the message when their were no replies and then never sent it. Now there's a lot of replies that already said what I had to say. Oops.

<small>[ April 10, 2003, 07:28 PM: Message edited by: photonic ]</small>

[nbk2000]

Movies are FICTION, not reality, so don't believe jack shit they say about "ammonia destroyed the blood" or any other such crap.

The safest bet is to use things intended to destroy organic matter...those things being drain cleaners. They're purpose is to dissolve and destroy hair, grease, and will also do that to skin and bone if you get it on you.

Highly concentrated acids, lye, oxidizers like hypochlorites and cyanurates, will all destroy organics. Pirahna fluid will do so with such violence as to cause ignition! And it's easy enough to carry around as a binary, mixed only at the instant of use.

In fact, the Drain-O foamer that has a two-compartment bottle is a Pirahna fluid, ready to use. :) One part is hypochlorite, the other hydrogen peroxide.

[DaRkDwArF]

Wouldn't be surprised about teh coke, I once tested the theory of using coke to lift oil stains on concrete driveways, it worked...

NBK's right on the mark, Drain-O packs sound like the go. Compressing acids into a can in a home workshop is not really a good idea...

[PyroTech]

You wouldn't need to compress them, just buy a little hairsprays bottle (the ones with the normal liquid inside, and a tube in the liquid, and a pump on top). They would do fine, won't spray 2 meters, but who needs that anyway.

And NBK, there is often a sence of reality used in movies, otherwise people would always start pissing that it's so fake, and it looked pretty real to me.

[darkdontay]

The point of Movies is to entertain not enlighten... It is hard to watch some movies cause they just gett all wierd in the science.
Chain Reaction,
The Core
The Manhattan Project.. and so on, yes many movies try and represent like they are real and it is supposed to be something realistic, but as allways it is desinged to look like that to entertain you.
Though if you look to moives as a guide for the stuff you do then may your deity help you.

[Bitter]

That's right, Einsteinium. Coke contains about 2% phosphoric acid.

[PyroTech]

Well darkdontay, as seen in the reactions of some users, there is something in that scene that's real, or close to real. And offcourse there are movies, were sience is all fantasy

And does anybody know, if you clean up some blood on a wall, with normal soap and water, and after that you'll spray it with bleach, does the blood still show up when the cops use luminol?(Spelling?)

In the program The FBI-Files, on discovery channel the cops use luminol alot, does anybody know what substance it is? For the ones who never check that program, and don't know Luminol, it's a spray that you spray on cleaned up blood, and it reacts with the blood, and when you turn the light off, it gives a kind of green/yellow light of. So you can see blood, even when somebody tried to clean up. I'm not sure everything is true in this post, since it was only a program.

[Einsteinium]

Even if my position about science in movies is the same as NBK's, I must say that discovery's programs are often a reliable source of infos, but not always.

I have heard of a case where, after some murderer violently exploded the head and legs of his victim with a mace, he then cleaned up his basement thouroughly with common bleach. Two years later a cop went there and tried up luminol, he found very slight luminescence thus sent some dirt to the lab. They couldn't do anything with it, except states that there were destroyed blood there. The cops then proceeded to remove a wooden stairway near the blood stains and found a minime, but intact, blood film stuck between two pieces of the stairway (the murderer had dragged his victim downstairs). Even after two years stuck there, their lab sequenced the DNA, which was indeed the victim's DNA, and caught the murderer.

One must be very careful when he destroys blood, spraying ammonia from a can (like the movie) then running away will only get you laughs... and time in jail.

<small>[ April 11, 2003, 03:05 PM: Message edited by: Einsteinium ]</small>

[Gargoylebrother]

While it is a very nice idea to be able to distroy DNA that easily i dont think ammonium would do it. I would sugest strong acid like S204 or HNO3 would probably work along with HCL. What i would want is if i had time to clean the area then test it with Luminol(sp) and make sure to check everywhere for small specks of blood or body fluids. If i remember right once in a CSI show i believe they said Luminol(sp) was used in some toilet bowl cleaners but im not sure. I think it would be great if one could find a good sorce of Luminol(sp) or a way to synthisize(sp) it. Also is there any other chemicals out there that work just like luminol(sp).

[PyroTech]

Sorry, there is already a topic about the substance Luminol. Chemistry related--&gt;Luminous solution...
Sorry for asking something that's allready in another topic.

[Ghostcustom 24]

I want to emphasis what Einsteinium said.
Destroying the blood is pointless, unless you destroy ALL of the blood. As he said even the smallest trace of undamaged blood is all that is needed.

For more unusual uses for Coke go <a href="http://members.tripod.com/~Barefoot_Lass/cola.html" target="_blank">Here</a>

[Anthony]

If I was wanting to destroy blood, I would get one of those big pump pressurised garden sprayers. Fill it with the liquid agent of choice and spray *everywhere*, several times. Obviously a respirator would be handy :)

[darkdontay]

You can destory blood with many things.. is that your only goal.. Bleach, Ammonia, Any strong Acid should break it down.

Are you trying to get rid of evidence that it was their.. Or just destroy the blood so as to make it useless fomr testings?

[Ghostcustom 24]

Good question. What is the goal of this scenario Pyro Tech?

[Einsteinium]

Are you trying to get rid of evidence that it was their.. Or just destroy the blood so as to make it useless fomr testings?
The two are almost the same... Even if you thouroughly clean a bloody place, there will still be evidence there, as forensic chemist can detect nucleotides fragments in the picograms amount. If one wants to make blood useless for testing, then he must destroy all the blood (thus most of the evidence) as it requires only a couple of micrograms to sequence it.

[darkdontay]

Might points was which one of these is he going from


1.) clrasytal clean sence.. nothign to find and also very little if any trace evidence left to shot that the sence had been cleaned...

2.) big huge pool of blood left in the middle of the carpet total rendered useless.

though there is alot of middle groun in between their and I understand that. I was taking the extremes to show my point of view.

[Einsteinium]

2.) big huge pool of blood left in the middle of the carpet total rendered useless.

That's what I was meant too, as it's not possible to exist. If there is a huge pool of blood, that's mean you failed in destroying most of it and there will certainly be a couple micrograms of intact DNA there. Destroyed blood is colorless and it dissolves in the destroying agent. Dried, it should looks like white crystals if completly destroyed, that dosen't look like blood at all. If there's still some red coloration in the "destroyed" blood, that means you definitivly failed in destroying it. I know you meant the extreme, but a minime reddish spot is way enough to sequence. Starting from there, to destroy evidence or to make blood useless for testing is almost the same.

[PyroTech]

Well, senario goes like this:

I have got to kill someone, I have no choice. It's a man, about 30 years old.

So I sneak into his house, I see him in the bathroom. Í'll go into the room, it's a weird bathroom, the floor is made of wood.

I shoot the guy, take whatever I need, and get out. I want to clear all the details; blood staines, little blood traces, maybe between the wood.

I'll come back the next day, and I strart cleaning, first the big things like blood on the wall, later I'll do the small things. But are the cops able to see the blood on the wall, with luminol? I cleaned it with soap and water, after that with some HCl, or bleach.

Do the cops have other ways of finding out? Note: I'll wear gloves, and will leave no trace of myself.

NOTE: THIS IS ALL JUST A THOUGHT!

[Einsteinium]

They'll probably find it if they try luminol, this stuff reacts with DNA and fragments of DNA, plus it is very sensitive. As I said, it worked (very slight glow) even two years after a scene has been cleaned up with bleach. It would be nice to have some luminol to check up yourself after cleaning a scene or another destroying agent than bleach or aqueous Acid/Base that products indetectable DNA fragments to luminol tests.

[Ghostcustom 24]

After checking with the luminol, you could use some very corrosive acids such as strong mineral acids or alkyl hydroxides. That should burn the walls/floor off and any trace of blood. :D

It would leave a rather permanent mark, but so would any acid poured on a wood floor.

[darkdontay]

Would "Killz" work to just paint over the walls.... I use it to cover Smoke damage, Smoke smell, Mildew, Mold..etc.. I wonder if it would be good enough to trap the eveidcne that their had been blood at al their? Just a Thought.

I will have to get a link to the information on that paint.

[Ghostcustom 24]

Not a bad idea if they had the time.
I would suggest using "Egg-shell" type paint. The reason for this being that this type of paint is extremely thick (hence the name:p) and widely available.

[PyroTech]

Well, painting would be ok.

But if the cops suspect that a crime has taken place, and there is one wall in a little different colour, I guess they would scrape some paint of the wall. And then they probably will be able to test the blood.

This is just a guess, who knows what paint will do to the blood. :-)

[vulture]

Use loads of nitric acid. Nitric acid is used in biology labs to destroy amino acids and any other type of organic matter left in filters, glassware, etc.

A possibly cheaper solution would be concentrated sulfuric acid with dissolved potassiumdichromate, as this has virtually the same effect and is strongly oxidizing.

[Tcell]

Admittedly this is a little late, but I wasn't particularly following this thread... The reason that stomach acid doesn't break down your DNA is because your stomach is protected by mucus membranes... Hence the reason why hard drinking (alcohol breaks down the mucus) can cause ulcers.

[mrcfitzgerald]

Since all one must do to "destroy" a sample of blood is to mutilate the DNA code
to the point where it would be either unsuitable for evidence, or match another person
besides the culprit; why not use intense UltaViolet radiation? Certain frequencies of UV
light (I believe higher rather than lower) cause intense mutation in the ATCG base pairs,
and since they cannot convict you unless the DNA matches the story (which in this case,
it dosent) your inoccent. Albeit the light wont be to good in penetrating carpet or fabrics,
only bleach will work there; however, given that you might need to rid a wall or ceiling of evidence,
instead of painting it, just go over thoroughly with the light. Of course if you wanted to avoid
all the trouble of decontaminating the area, you might as well just burn down the building.

[Ghostcustom 24]

Yes burning the building down is a most effective method, after you exhausted all other methods of destroying the blood DNA.

[Chade]

I had the idea ages ago, searched and found this thread, and was a litle suprised to see no one mention it. If, for example, I'd killed someone in my house, and wanted to remove the blood stains, I'd clean them with conventional cleaning products as thoroughly as possible.
Then I'd paint everywhere that I'd cleaned with Pigs blood. Then I'd clean that up.

See that'll make any DNA harder to find amongst the pig DNA. Not impossible, mind you, but you've also cleaned it twice rather than once, and the pig blood should be greatly in excess of the human blood.

It is very possible to tell different species by detecting the number of chromosomes. I'm not sure how many pigs have, but I think it's not the same as humans.

DNA testing relies on PCR.
What they do is duplicate (so to speak) the replication process that goes on for DNA in cells. The DNA is put in a solution, split down the middle, then each half combines with bases (Like ACTG, although, if I remember right I think another one may be involved during duplication) So you now have two strands of DNA. Repeat, and get enough DNA to test.
Now, it'd be nice if this meant you could just chuck in any old DNA to screw up their testing with noise, but much of the work in PCR (and it's difficult enough to manage anyway) is to chop off a specific chunk. For example, a point in the human DNA structure would be isolated, for example they could isolate a region on a Y chromosome if they knew they were looking to ID a mans DNA, then just duplicate that section.
So anyway, their PCR process will ignore the pigs blood, but it should screw up quite a few other tests they use, including general tests for blood. If I remember correctly, Pigs internal organs are remarkably similar to Humans, so I'd guess their blood might be similar too. I suppose ape blood would be better, but harder to acquire than just trotting down the butcher shop. You could even bleed yourself and keep your blood frozen for such an eventuality. Although I don't think I'd want to try that, that really would screw up their tests.
'Yes, we have conclusive proof that he killed... ...himself?'

[McGyver]

Anyone watch Mythbusters on Discovery channel? Well they were testing the myth of coke disolving a steak, they left the steak in the coke for a day and it didn't do anything to it exept tint it a brown color. So if you left the the stake longer the coke wouldn't dissolve it that much, it would just decay like all meats. They also tried to wash of animal blood of the road with coke, it worked very well.

[xyz]

When you are using coke to dissolve things, it has to be fresh out of the bottle and it loses most of it's dissolving power within a few hours.

The dissolving power of coke is mostly due to the carbonic acid in it that starts decomposing into CO2 and water once the bottle is opened and the pressure released, this is why coke goes "flat".

There is a small amount of phosphoric acis in coke as well but it is not enough to do any noticeable dissolving.

[Wild Catmage]

I learnt something in biochemistry today :) - Strong acids and alkalis can denature proteins. A change in pH alters the charges on the R g
groups of certain amino acids, and so disrupts ionic bonds. Prolonged exposure to acid or alkali can even break the peptide linkages between amino acids.

"The tissue of the stomach is protected by a later of mucus into which bicarbonate is secreted as an acid neutralizer. The integrity of this mucus lining keeps us from being burned by our own stomach acid." -http://www.marvistavet.com/html/body_helicobacter_infection.html

[Ammonal]

I hate to sound stupid but someone once said "that there is no such thing as a stupid question, only a stupid answer" besides the point. My old lady is a nurse and I just recalled a conversation with her about cleaning up the outpatients room after someone came in with their arm torn off from a grain auger... the person was apparently bleeding profusely. This person survived and after they shipped him off to a ward the nurses had to clean the outpatients room (emergency ward?) she told me that they used a battery powered Blacklight fluorescent tube which made all the blood stand out like magic markers do under blacklights.
If this is the case why use 'Luminol' and darkness to find blood traces when a black light is much simpler. I may well be wrong but I thought it was worth asking.

[Kid Orgo]

"eggshell" refers to the color of paint, not a type. It's a slightly yellow off white. Enamels tend to go on thick, but that's not really relevant.

The shit painters use to really seal the fuck out of a stained surface is a shellac-based paint made by Zinsser, called BIN. Almost nothing will leech through a coat or two of BIN. You can then throw a matching color on top of it, and it'll cover.

As a practical note, it's best to mix the BIN (white) with a color near that of the one you'll paint over it (oil or water based) so it'll cover better, saving you an extra coat or two.

[apathyboy]

I was reading this thread, and it seems like there's some confusion as to what luminol does. It does not react with DNA, but with the iron (hemoglobin) in your blood. While destroying the DNA with something like lye might make it impossible to identify who's blood it is, it still leaves you the problem of explaining to the cops how your basement got sprayed with huge arcs of blood, which apparently makes them suspicious.

http://www.deakin.edu.au/forensic/Chemical%20Detective/Luminol_test.htm

You could always get around that by pretending to commit suicide: waste your co-worker/significant other/pizza boy, dispose of their body (dinner anyone?), and clean up with some lye. Slit your own wrists and flail about for a bit before "you realize you have too much to live for" and call an ambulance. Simple explanation for the blood, and most people wouldn't accuse someone who just tried to kill themselves of a murder.

Or, being the mad scientists you all are (have neighbours who hear the loud booms and cursing coming from your yard explain this), just liberally dust/spray the place with whatever iron compound you happen to have handy, and tell the cops that one of your experiments exploded and covered the place in iron. They'd never believe that one person's blood covered an entire floor of your house.

[Rhadon]

It does not react with DNA, but with the iron (hemoglobin) in your blood. When I got it right the luminol does react with certain iron(III)-, copper- and cyanide compounds. If it's true, you could do what apathyboy proposed and just paint all walls of the room which is spilled with blood with a color that contains and a large amount of a suitable substance, thus covering the characteristic shape of blood stains (which would give you away) with a uniform luminescence (so you don't even need pigs' blood for it). But I wouldn't say that the scene is covered with the substance because of an explosion (this would make you prone for further investigations) but because you liked to paint the room with a color which you made yourself. Copper compounds might be a good choice for that.

I just found something about experiments that have been done with luminol:
From our experimental results, luminol glows strongest in alkaline medium - e.g. common cleaning agents, which means the glowing of luminol will usually be even brighter after the blood-stained materials are washed by the criminals with alkaline cleaning agents. Among the agents tested, luminol glows strongest when the blood stain is washed with bleach. It is most advisable to conduct the test at around thirty degree Celsius. Luminol still glows in the presence of different organic solvents and on different working surfaces. Through our further investigations, not all Fe(III) ions can catalyse this reaction as iron in haemoglobins do. It is shown that reaction of luminol with H2O2 is an oxidation instead of reduction, and that it would be hindered, but not destroyed, by acid.

[IDTB]

This may not be too helpful, but I figured I should throw it out there. I hear cows blood is almost identical, or at least usable to humans. So, it must have alot of consistances with ours. If you were to contaminate a crime scene with large amounts of cow blood(think, with reason) would they test every bit of it or would they go with an assumption?

[dana_m_h]

i have a bright idea (real bright lol) go out on a wrought iron balcony and spray down the area your standing and spray it down every 2-3 mins with some HCl and do this on the 5th floor or higher. this is if you have to clean up blood from a murder do not do this otherwise because spraying things with HCl isnt smart (just lettin you ppl know if you did spray stuff with HCl you will end up with acid burns on you ,your stuff, your apartment and the police will be suspicious about the acid holes through your floor) [yes in chem class acid will burn through about anything my teacher heated a big beaker of HCl too fast and the beaker shattered spilling acid across the floor it burned through the linolium in some places in under 5 mins. 1 spot he missed burned through the lab table (1-1/2 inch coated wood)]




if this post offends anyone i dont mean it i wrote in 3 minuits ona caffine high hehehehe

[Chade]

After a few more chem classes, you might notice the acids get less powerful as they get more dilute. There's no problem using this on a patio (HCl is sold as patio cleaner for that purpose), or on resistant plastics and masonry. I don't think anyone was suggesting shampooing their carpets with HCl (at least I hope not) but bleach will also screw up your clothes, and most people use that when they're cleaning up without any significant property damage.

Now that it occurs to me, as far as carpets and curtains go, I think a solution of biological washing powder would work very well. After all, that's designed to attack a whole range of organic molecules, presumably the enzymes would attack the blood cells themselves, and possibly the DNA within them too.

[Jacks Complete]

Chade said:

biological washing powder

Strange. I was telling my parents a similar thing last night, about a rat that ate some dishwasher tablets. We figure it didn't eat, just knawed, as it is still alive. Anyway, point is, in Chemistry A-level, we did some stuff on biological washing powder, soap, dishwasher tablets, etc.

Modern automatic powders are so powerful they will eat holes through cotton if you leave them in it.

Use a warm solution (40 degree wash?) and it will rip through anything biological. The enzymes just eat everything - blood, egg, gravy. You have seen the adverts!

I recall we put something like a chicken leg into one beaker, and it stripped the flesh off over a few weeks. The crud in a dishwasher gets even harsher treatment, and dissolves away.

That would do for a few traces of blood or whatever.

Of course, we need to know for sure. DNA is pretty fragile once it is out of the protection of the cell - it will oxidise in air, for example, but even a trace can be a problem.

Anyone done biology and chemistry, who can think of a sure test?

[Psyiko]

hey yall, is 6 M HCl enough to denature the blood?