megalomania
June 26th, 2003, 03:53 PM
nbk2000
Moderator
Posts: 1135
From: Guess
Registered: SEP 2000
posted March 10, 2001 01:40 PM
--------------------------------------------------------------------------------
Luminol, for those of you who don't know what it is, is a chemical that reacts with the iron content of blood, forming a green glow when exposed to UV light that reveals the presence of otherwise invisible bloodstains.
This has lead to the detection of otherwise perfect murders that were thought of as suicides, until a glowing green trail from a bed to the bathtub is detected.
I have 3 ideas about how to defeat the use of luminol:
1. Use a chelation agent like EDTA to combine with the iron and make it unavailable to react with the luminol.
2. Use chemicals that react with iron to make it totally soluable in water and able to be washed completely away with no traces left to be detected. Vitamin C reacts with iron to form iron soluble salts and is inert to most materials. Cheap too.
3. Make the detection of iron a moot point. Use a sprayer filled with a suitable iron chemical and spray the entire crime scene, floor to ceiling, with it. Then anywhere they use the luminol, they're going to get a glow. Remember, the lack of positive evidence is not in and of itself evidence.
Possible problems would be that luminol may only react with certain iron compounds or in the presence of some other blood component. Wheter this is possible, I don't know.
Anyone with suitable knowledge to provide intelligent feedback on this subject is encouraged to reply. NO LAMERZ!
------------------
"The knowledge that they fear is a weapon to be used against them"
Go here to download the NBK2000 website PDF.
Jhonbus
Frequent Poster
Posts: 347
From:
Registered: SEP 2000
posted March 10, 2001 02:01 PM
--------------------------------------------------------------------------------
As soon as I started reading this topic, I thought of idea number 3
I think it would cause extreme suspicion, and make them look all the harder for other evidence, but it's a sound idea.
I don't think idea 1 would work because the iron in blood is already chelated by the haemoglobin complex. Not completely sure about this though.
Idea 2 sounds like it would work quite well.. but washing away the iron-containing compound might still be quite difficult.
blackadder
Frequent Poster
Posts: 313
From: London
Registered: DEC 2000
posted March 10, 2001 02:24 PM
--------------------------------------------------------------------------------
What will the police's reaction be, when they see that the whole room glows? They won't think "This person smeared blood everywhere", what would they think? What reason could you possibly have for having the whole room covered in the stuff?
No doubt they would be extremely suspicious, but they will be ultra-confused as well.
Surely they know that people can develop tactics to defeat luminol?
Bitter
Frequent Poster
Posts: 293
From: 11 Downing Street, London, England
Registered: SEP 2000
posted March 10, 2001 02:30 PM
--------------------------------------------------------------------------------
I have a little EDTA available if you want to do any experimentation, NBK.
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted March 10, 2001 03:21 PM
--------------------------------------------------------------------------------
We ARE talking about getting the details correct for a new crime novel, not plotting an actual murder, right? Okay.
Playing "devil's advocate" for a moment, a couple of thoughts:
Wouldn't the chelation agent have to be such that it left no detectable residue of its own? After all, the "evidence" collected in a luminol scan is a photographic record of blood traces detected - not the actual blood itself. If they could figure out what had been done, photos demonstrating that certain areas had been treated to render luminol ineffective might be just as incriminating.
Luminol may be iron-reactive, but iron isn't the only thing they look for at crime scenes. From what I understand there are many tests for the presence of blood, and the tests done on wood, fabrics, the contents of drains etc. aren't limited to luminol. While they probably wouldn't remove floorboards to a lab without thinking there was something to find, the same might not be true of fabrics or drain contents.
The problem with "painting" the scene with an iron solution (or some such) is that deliberate contamination would immediately be apparent. This would shift the focus to HOW, WHY, and more importantly WHEN? The vagaries of aerosol dispersion being what they are, unless the scene could literally be flooded it could easily be deduced the contamination took place after the fact - proof positive the "death" had not been a suicide or accidental. If there had been any uncertainty before, this would remove it.
I don't know either about whether luminol reacts with iron only in the presence of other blood products, but I don't think I'd care to educate myself by reading lab reports with my name on them.
Similarly, where my defense argument rested solely on the inability of police to detect blood in the face of evidence the blood traces had been destroyed, I wouldn't be overly reliant on the average jury to parse the finer points of evidence law.
It's an interesting question nonetheless, and one analogous to preventing fingerprint detection. It's been shown that even this requires a complex "cocktail" of chemicals to reliably defeat the silver nitrate, iodine, cyanoacrylate, neopicrin, UV, and laser detection methods used by crime labs in fingerprint recovery. I'd venture a guess that blood products might be trickier still to deal with.
BoB-
Frequent Poster
Posts: 657
From:
Registered: SEP 2000
posted March 10, 2001 07:08 PM
--------------------------------------------------------------------------------
I found some info on Luminol, its apperently a chem-illuminescence constituent.
You can make it give off light by mixing 0.60 gm Luminol and 3.30 gm NaOH per 2000 ml,
and then pouring the solution into a solution of 6.1 gm K3Fe(CN)6 [or 7.8 gm K3Fe(CN)6.H2O] per 2000 ml, and then add 2 ml 30% H2O2 per 200 ml of solution, the mix will glow in low light (you can find a much more detailed description here.
Human blood contains a pigment called haemoglobin, the central atom of haemoglobin is Fe (iron)
Here I found this:
http://www.deakin.edu.au/forensic/Chemical%20Detective/images/luminol_gif.gif
I have to agree with c0deblue, a counter-agent would be proof of foulplay.
[This message has been edited by BoB- (edited March 10, 2001).]
Mr Cool
Frequent Poster
Posts: 991
From: None of your bloody business!
Registered: DEC 2000
posted March 11, 2001 11:16 AM
--------------------------------------------------------------------------------
You can oxidise luminol with H2O2 at the right pH etc. to produce a bright blue glow. Not useful, but quite pretty Looks good if you spray it from an atomiser in the dark.
Agent Blak
Frequent Poster
Posts: 770
From: Sk. Canada
Registered: SEP 2000
posted March 11, 2001 11:24 PM
--------------------------------------------------------------------------------
How un common is it for a suicide to be followed be arson. Would fire not destroy the evidence? if you were good you would set it up so it looked like they were going to try and fuck over the insurence company and fucked up. not un common. Plus why not use a garrot no messy blood; you could also make that look like they use a poorly made knose and it choled them to death not *snap* there neck.
------------------
A wise man once said:
"...I Am Not Much of a Dancer But,
Just Wait Till The Fucking Begins"
Agent Blak-------OUT!!
DaRkDwArF
Frequent Poster
Posts: 258
From: Australia
Registered: SEP 2000
posted March 13, 2001 03:48 AM
--------------------------------------------------------------------------------
First gunpowder, now a cover up, isn't Vitamin C just wonderful!
hmmm, a lot of gear involved in "The Perfect Murder" but these are a lot of things nobody thinks of, I've seen this product used in a forensics video and it even showed the forensics team how the murder was done by the blood pattern, eg. if they were hit by a baseball bat the blood pattern would be slight arched, yet a gunshot wound would present a different pattern. and they could go further into it like the caliber of the firearm used or the shape of the weapon, was rather interesting and yes I went to the police museum to see this =)
megalomania
Administrator
Posts: 653
From: USA
Registered: SEP 2000
posted March 17, 2001 12:51 PM
--------------------------------------------------------------------------------
Offhand I would have to say that if you spray luminol on the crime scene yourself, it should bind all of the iron in the blood, thus rendering furthur luminol detection impossible. I have made luminol before, I will have to consult my info on it to see if this is feasible.
The idea of rendering the iron unavailable is by far the best way. Luminol cannot react with it if it is already in a compound. Combining a better cleaning method with binding the iron is better still.
And why don't crooks defeat luminol more often? Well, quite frankly the police rely on the stupidity of the crook.
------------------
For the most comprehensive and informative web site on explosives and related topics, go to Megalomania's Explosives and Stuff at http://surf.to/megalomania
nbk2000
Moderator
Posts: 1135
From: Guess
Registered: SEP 2000
posted March 18, 2001 12:30 PM
--------------------------------------------------------------------------------
After doing some web searching this is what I've found out about luminol:
Luminol requires oxidized blood (released oxygen) to glow. To accomplish this the luminol solution contains an oxidant like hydrogren peroxide or sodium perborate. It is the released oxygen that catalyzes the luminescence.
The iron in blood is what's oxidized and this is what the luminol detects. But it also reacts (false positives) with copper ions, copper compounds, iron compounds (like rust), and cobalt ions, potassium permanganate (found in some dyes),sodium hypochlorite
(bleach), ferricyanide, plant peroxidases, and even cigarette smoke. Some of these false positives can be differentied by spectral analysis, but this would require a spectrometer which might be difficult to set up on site.
Also, there is insufficient difference between human and bovine (cow) haemoglobin to distinguish between them using spectral differences. So this might be useful for decoy blood stains.
Luminol can detect blood traces down to 1 part in 5 million, but the luminol reaction is at best a presumptive test for blood. If the stain is so dilute that it can only be visualized with luminol, then no further analysis can be performed to confirm the presence of blood.
Also, studies have shown that luminol will cause the loss of several genetic
markers because luminol is water based, and it can cause latent, possibly bloody
impressions to smear. Luminol can also further dilute an already diluted
stain. This may push the stain beyond the genetic marker analysis detection.
Some links to visit:
Simple explaination of how luminol works:
http://www.deakin.edu.au/forensic/Chemical%20Detective/Luminol_test.htm
Real Video of luminol in action:
http://play.rbn.com/?url=dcionline/dcionline/g2demand/fansites/new_detectives/ dark.rm&proto=rtsp
Using luminol to detect blood:
http://www.ualr.edu/~cjdept/ci/blood.pdf
List of substances that cause false postives:
http://www.redwop.com/technotes.asp?ID=118
PDF version of above:
http://www.redwop.com/download/hemaglow.pdf
(or see attached)
Since the iron in the haemoglobin molecule is very tightly bound in, and blood stains are detectable even years later, I don't think that trying to bind something to the iron would work. Because anything that would bind to the iron would first have to have freed it from the haemoglobin, which means it's free to be washed away.
Anything that binds with the iron will have to be irreversible bound to it and be able to resist breakdown by peroxides and hydroxides.
So I think the washing agent idea would be the most productive.
And I've read of how the luminol can keep being reapplied to the same stain over and over with repeatable results so trying to bind it with luminol is a no-go. But it could be used by you to find the stains and use the effective washing agent.
There's several places that sell luminol. As low as $25 for a pint of mix. This would have to be purchased long ahead of time so there's be no incriminating records to point back to you.
Yes, most criminals are stupid. They either do it in the heat of the moment and are thus unprepared, or they plot and scheme but overlook the simplist things like "Who took out a million dollar life insurance policy 1 week before the victim died in a freak squirrel hunting accident?".
Moderator
Posts: 1135
From: Guess
Registered: SEP 2000
posted March 10, 2001 01:40 PM
--------------------------------------------------------------------------------
Luminol, for those of you who don't know what it is, is a chemical that reacts with the iron content of blood, forming a green glow when exposed to UV light that reveals the presence of otherwise invisible bloodstains.
This has lead to the detection of otherwise perfect murders that were thought of as suicides, until a glowing green trail from a bed to the bathtub is detected.
I have 3 ideas about how to defeat the use of luminol:
1. Use a chelation agent like EDTA to combine with the iron and make it unavailable to react with the luminol.
2. Use chemicals that react with iron to make it totally soluable in water and able to be washed completely away with no traces left to be detected. Vitamin C reacts with iron to form iron soluble salts and is inert to most materials. Cheap too.
3. Make the detection of iron a moot point. Use a sprayer filled with a suitable iron chemical and spray the entire crime scene, floor to ceiling, with it. Then anywhere they use the luminol, they're going to get a glow. Remember, the lack of positive evidence is not in and of itself evidence.
Possible problems would be that luminol may only react with certain iron compounds or in the presence of some other blood component. Wheter this is possible, I don't know.
Anyone with suitable knowledge to provide intelligent feedback on this subject is encouraged to reply. NO LAMERZ!
------------------
"The knowledge that they fear is a weapon to be used against them"
Go here to download the NBK2000 website PDF.
Jhonbus
Frequent Poster
Posts: 347
From:
Registered: SEP 2000
posted March 10, 2001 02:01 PM
--------------------------------------------------------------------------------
As soon as I started reading this topic, I thought of idea number 3
I think it would cause extreme suspicion, and make them look all the harder for other evidence, but it's a sound idea.
I don't think idea 1 would work because the iron in blood is already chelated by the haemoglobin complex. Not completely sure about this though.
Idea 2 sounds like it would work quite well.. but washing away the iron-containing compound might still be quite difficult.
blackadder
Frequent Poster
Posts: 313
From: London
Registered: DEC 2000
posted March 10, 2001 02:24 PM
--------------------------------------------------------------------------------
What will the police's reaction be, when they see that the whole room glows? They won't think "This person smeared blood everywhere", what would they think? What reason could you possibly have for having the whole room covered in the stuff?
No doubt they would be extremely suspicious, but they will be ultra-confused as well.
Surely they know that people can develop tactics to defeat luminol?
Bitter
Frequent Poster
Posts: 293
From: 11 Downing Street, London, England
Registered: SEP 2000
posted March 10, 2001 02:30 PM
--------------------------------------------------------------------------------
I have a little EDTA available if you want to do any experimentation, NBK.
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted March 10, 2001 03:21 PM
--------------------------------------------------------------------------------
We ARE talking about getting the details correct for a new crime novel, not plotting an actual murder, right? Okay.
Playing "devil's advocate" for a moment, a couple of thoughts:
Wouldn't the chelation agent have to be such that it left no detectable residue of its own? After all, the "evidence" collected in a luminol scan is a photographic record of blood traces detected - not the actual blood itself. If they could figure out what had been done, photos demonstrating that certain areas had been treated to render luminol ineffective might be just as incriminating.
Luminol may be iron-reactive, but iron isn't the only thing they look for at crime scenes. From what I understand there are many tests for the presence of blood, and the tests done on wood, fabrics, the contents of drains etc. aren't limited to luminol. While they probably wouldn't remove floorboards to a lab without thinking there was something to find, the same might not be true of fabrics or drain contents.
The problem with "painting" the scene with an iron solution (or some such) is that deliberate contamination would immediately be apparent. This would shift the focus to HOW, WHY, and more importantly WHEN? The vagaries of aerosol dispersion being what they are, unless the scene could literally be flooded it could easily be deduced the contamination took place after the fact - proof positive the "death" had not been a suicide or accidental. If there had been any uncertainty before, this would remove it.
I don't know either about whether luminol reacts with iron only in the presence of other blood products, but I don't think I'd care to educate myself by reading lab reports with my name on them.
Similarly, where my defense argument rested solely on the inability of police to detect blood in the face of evidence the blood traces had been destroyed, I wouldn't be overly reliant on the average jury to parse the finer points of evidence law.
It's an interesting question nonetheless, and one analogous to preventing fingerprint detection. It's been shown that even this requires a complex "cocktail" of chemicals to reliably defeat the silver nitrate, iodine, cyanoacrylate, neopicrin, UV, and laser detection methods used by crime labs in fingerprint recovery. I'd venture a guess that blood products might be trickier still to deal with.
BoB-
Frequent Poster
Posts: 657
From:
Registered: SEP 2000
posted March 10, 2001 07:08 PM
--------------------------------------------------------------------------------
I found some info on Luminol, its apperently a chem-illuminescence constituent.
You can make it give off light by mixing 0.60 gm Luminol and 3.30 gm NaOH per 2000 ml,
and then pouring the solution into a solution of 6.1 gm K3Fe(CN)6 [or 7.8 gm K3Fe(CN)6.H2O] per 2000 ml, and then add 2 ml 30% H2O2 per 200 ml of solution, the mix will glow in low light (you can find a much more detailed description here.
Human blood contains a pigment called haemoglobin, the central atom of haemoglobin is Fe (iron)
Here I found this:
http://www.deakin.edu.au/forensic/Chemical%20Detective/images/luminol_gif.gif
I have to agree with c0deblue, a counter-agent would be proof of foulplay.
[This message has been edited by BoB- (edited March 10, 2001).]
Mr Cool
Frequent Poster
Posts: 991
From: None of your bloody business!
Registered: DEC 2000
posted March 11, 2001 11:16 AM
--------------------------------------------------------------------------------
You can oxidise luminol with H2O2 at the right pH etc. to produce a bright blue glow. Not useful, but quite pretty Looks good if you spray it from an atomiser in the dark.
Agent Blak
Frequent Poster
Posts: 770
From: Sk. Canada
Registered: SEP 2000
posted March 11, 2001 11:24 PM
--------------------------------------------------------------------------------
How un common is it for a suicide to be followed be arson. Would fire not destroy the evidence? if you were good you would set it up so it looked like they were going to try and fuck over the insurence company and fucked up. not un common. Plus why not use a garrot no messy blood; you could also make that look like they use a poorly made knose and it choled them to death not *snap* there neck.
------------------
A wise man once said:
"...I Am Not Much of a Dancer But,
Just Wait Till The Fucking Begins"
Agent Blak-------OUT!!
DaRkDwArF
Frequent Poster
Posts: 258
From: Australia
Registered: SEP 2000
posted March 13, 2001 03:48 AM
--------------------------------------------------------------------------------
First gunpowder, now a cover up, isn't Vitamin C just wonderful!
hmmm, a lot of gear involved in "The Perfect Murder" but these are a lot of things nobody thinks of, I've seen this product used in a forensics video and it even showed the forensics team how the murder was done by the blood pattern, eg. if they were hit by a baseball bat the blood pattern would be slight arched, yet a gunshot wound would present a different pattern. and they could go further into it like the caliber of the firearm used or the shape of the weapon, was rather interesting and yes I went to the police museum to see this =)
megalomania
Administrator
Posts: 653
From: USA
Registered: SEP 2000
posted March 17, 2001 12:51 PM
--------------------------------------------------------------------------------
Offhand I would have to say that if you spray luminol on the crime scene yourself, it should bind all of the iron in the blood, thus rendering furthur luminol detection impossible. I have made luminol before, I will have to consult my info on it to see if this is feasible.
The idea of rendering the iron unavailable is by far the best way. Luminol cannot react with it if it is already in a compound. Combining a better cleaning method with binding the iron is better still.
And why don't crooks defeat luminol more often? Well, quite frankly the police rely on the stupidity of the crook.
------------------
For the most comprehensive and informative web site on explosives and related topics, go to Megalomania's Explosives and Stuff at http://surf.to/megalomania
nbk2000
Moderator
Posts: 1135
From: Guess
Registered: SEP 2000
posted March 18, 2001 12:30 PM
--------------------------------------------------------------------------------
After doing some web searching this is what I've found out about luminol:
Luminol requires oxidized blood (released oxygen) to glow. To accomplish this the luminol solution contains an oxidant like hydrogren peroxide or sodium perborate. It is the released oxygen that catalyzes the luminescence.
The iron in blood is what's oxidized and this is what the luminol detects. But it also reacts (false positives) with copper ions, copper compounds, iron compounds (like rust), and cobalt ions, potassium permanganate (found in some dyes),sodium hypochlorite
(bleach), ferricyanide, plant peroxidases, and even cigarette smoke. Some of these false positives can be differentied by spectral analysis, but this would require a spectrometer which might be difficult to set up on site.
Also, there is insufficient difference between human and bovine (cow) haemoglobin to distinguish between them using spectral differences. So this might be useful for decoy blood stains.
Luminol can detect blood traces down to 1 part in 5 million, but the luminol reaction is at best a presumptive test for blood. If the stain is so dilute that it can only be visualized with luminol, then no further analysis can be performed to confirm the presence of blood.
Also, studies have shown that luminol will cause the loss of several genetic
markers because luminol is water based, and it can cause latent, possibly bloody
impressions to smear. Luminol can also further dilute an already diluted
stain. This may push the stain beyond the genetic marker analysis detection.
Some links to visit:
Simple explaination of how luminol works:
http://www.deakin.edu.au/forensic/Chemical%20Detective/Luminol_test.htm
Real Video of luminol in action:
http://play.rbn.com/?url=dcionline/dcionline/g2demand/fansites/new_detectives/ dark.rm&proto=rtsp
Using luminol to detect blood:
http://www.ualr.edu/~cjdept/ci/blood.pdf
List of substances that cause false postives:
http://www.redwop.com/technotes.asp?ID=118
PDF version of above:
http://www.redwop.com/download/hemaglow.pdf
(or see attached)
Since the iron in the haemoglobin molecule is very tightly bound in, and blood stains are detectable even years later, I don't think that trying to bind something to the iron would work. Because anything that would bind to the iron would first have to have freed it from the haemoglobin, which means it's free to be washed away.
Anything that binds with the iron will have to be irreversible bound to it and be able to resist breakdown by peroxides and hydroxides.
So I think the washing agent idea would be the most productive.
And I've read of how the luminol can keep being reapplied to the same stain over and over with repeatable results so trying to bind it with luminol is a no-go. But it could be used by you to find the stains and use the effective washing agent.
There's several places that sell luminol. As low as $25 for a pint of mix. This would have to be purchased long ahead of time so there's be no incriminating records to point back to you.
Yes, most criminals are stupid. They either do it in the heat of the moment and are thus unprepared, or they plot and scheme but overlook the simplist things like "Who took out a million dollar life insurance policy 1 week before the victim died in a freak squirrel hunting accident?".