Continuation Part 4: Discussion of the Amanda Knox/Raffaele Sollecito case

[Supernaut]

Fascinating that there is a lawyer that is too good for this world -

What do you all think was the substance that produced the luminol discovered footprints in the cottage? Not the shoe-prints.

"The first thing we do, let's kill all the lawyers" - Henry VI (Part 2) .

 

[Chris_Halkides]

Bleach seems to decay more quickly on floors than in bottles.

Thanks for clearing that up. Want to try English next time?? Only joking, but seriously, could you try and explain that so those of without chemistry degrees understand it?

There was a paper which noted that the reaction of luminol with bleach on a floor was very dependent on how long ago the bleach was applied. After about a day, the bleach reaction was pretty much absent (see also this link). My point was that this does not seem to square with our everyday experience of bleach, which is that we buy it and use it weeks later. The bleach probably decomposes at a much, much slower rate in a bottle than it decomposes on a floor, but I am unsure of the reason.

 

[Chris_Halkides]

The footprint in Amanda's room

What do you all think was the substance that produced the luminol discovered footprints in the cottage? Not the shoe-prints.

Consider Rep. 180 from Amanda's room. The luminol image clearly does not match Amanda's second toe. I have heard people argue that maybe she scrunched her toe when she made that image, but I don't buy it. All my toes curl up when I try to scrunch up my second toe. Let's take that the image is not of her foot as a given, and see where it gets us. The image would most likely have been created prior to 1 November, because there is no reason for someone to have been going barefoot in Amanda's room after that time. If so, then the substance that gave rise to the luminol is unlikely to be blood: who would have been stepping in bloody or bloody water in the weeks leading up to the murder? If Rep. 180 did not arise from blood, then why should we believe that any other footprint is blood?

Other photos show that something on one of the investigator's boots reacted with luminol. IIRC so did something on a ruler in one photograph. These photos were discussed at Websleuths some time ago. With respect to TMB, I basically agree with Kaosium. TMB is sometimes used after luminol, but it is not a true confirmatory test.

 

[anglolawyer]

Consider Rep. 180 from Amanda's room. The luminol image clearly does not match Amanda's second toe. I have heard people argue that maybe she scrunched her toe when she made that image, but I don't buy it. All my toes curl up when I try to scrunch up my second toe. Let's take that the image is not of her foot as a given, and see where it gets us. The image would most likely have been created prior to 1 November, because there is no reason for someone to have been going barefoot in Amanda's room after that time. If so, then the substance that gave rise to the luminol is unlikely to be blood: who would have been stepping in bloody or bloody water in the weeks leading up to the murder? If Rep. 180 did not arise from blood, then why should we believe that any other footprint is blood?

Why couldn't the image be made on 01 Nov? I don't think I follow.

 

[Chris_Halkides]

My nonprofessional take on it

Why couldn't the image be made on 01 Nov? I don't think I follow.

If it were made on November 1 and arose from Meredith's blood, there would have had to have been a second female involved in the crime, one whose footprint is a better match for the image than Amanda's is. I am not an expert in footprints or shoe prints, but the luminol image does not look the same as her reference print looks, and not just in the second toe.

 

[anglolawyer]

If it were made on November 1 and arose from Meredith's blood, there would have had to have been a second female involved in the crime, one whose footprint is a better match for the image than Amanda's is. I am not an expert in footprints or shoe prints, but the luminol image does not look the same as her reference print looks, and not just in the second toe.

I get it. Thanks. Wonder who it was. Sophie probably.

 

[acbytesla]

There was a paper which noted that the reaction of luminol with bleach on a floor was very dependent on how long ago the bleach was applied. After about a day, the bleach reaction was pretty much absent (see also this link). My point was that this does not seem to square with our everyday experience of bleach, which is that we buy it and use it weeks later. The bleach probably decomposes at a much, much slower rate in a bottle than it decomposes on a floor, but I am unsure of the reason.

Well wouldn't that be the result of a small amount of bleach that is on the surface of the floor being constantly exposed to oxygen on the floor?

While I'm sure there is some oxygen that is sealed in the open air part of bottle, I would imagine its only oxidizes the surface of the bleach which would be nominal compared to the volume of bleach in the bottle?

 

[Grinder]

There was a paper which noted that the reaction of luminol with bleach on a floor was very dependent on how long ago the bleach was applied. After about a day, the bleach reaction was pretty much absent (see also this link). My point was that this does not seem to square with our everyday experience of bleach, which is that we buy it and use it weeks later. The bleach probably decomposes at a much, much slower rate in a bottle than it decomposes on a floor, but I am unsure of the reason.

Thanks for the cite. This is much of what I have come to believe as I stated above. I know that acetone will disappear fast if one doesn't put the cap back on. I assume that the bleach in a bottle mixes with the air inside until the air can't hold anymore of the bleach vapors and the liquid bleach remaining stays at the same strength.

Consider Rep. 180 from Amanda's room. The luminol image clearly does not match Amanda's second toe. I have heard people argue that maybe she scrunched her toe when she made that image, but I don't buy it. All my toes curl up when I try to scrunch up my second toe. Let's take that the image is not of her foot as a given, and see where it gets us. The image would most likely have been created prior to 1 November, because there is no reason for someone to have been going barefoot in Amanda's room after that time. If so, then the substance that gave rise to the luminol is unlikely to be blood: who would have been stepping in bloody or bloody water in the weeks leading up to the murder? If Rep. 180 did not arise from blood, then why should we believe that any other footprint is blood?

For right now let's not worry about whether any or all of the prints are Amanda's. Let's assume they are not the result of blood. Let's assume that 6 weeks later that they weren't caused by bleach.

What substance would have survived a floor cleaning and only left a relatively few prints? A spilled bottle of juice that was stepped in? But why didn't anybody recall that? Maybe as Raf no one asked.

If the floor hadn't been cleaned since the prints that would seem to make relatively recent considering all the other girls having such good house cleaning skills.

Other photos show that something on one of the investigator's boots reacted with luminol. IIRC so did something on a ruler in one photograph. These photos were discussed at Websleuths some time ago. With respect to TMB, I basically agree with Kaosium. TMB is sometimes used after luminol, but it is not a true confirmatory test.

Okay, but since luminol isn't obviously a confirming test, then what is?

 

[acbytesla]

Okay, but since luminol isn't obviously a confirming test, then what is?

It is a presumptive test as is TMB. It is the combination of tests since both react to different substances.

It is the intersecting substances that narrow the possibilities.

 

[Grinder]

It is a presumptive test as is TMB. It is the combination of tests since both react to different substances.

It is the intersecting substances that narrow the possibilities.

They both react to blood. Supposedly one is more sensitive. The luminol reacted and produced the blue glow. The ILE said they coulkd tell it was blood from the strength of the glow. They at first denied the TMB (Or is that TBM )
test had been done and came out as a negative.

Luminol also is reported to possibly destroy samples for subsequent tests. They seemed to have over-sprayed the luminol.

ETA - here's what Kaosium said "TMB gives false positives, thus a positive with TMB doesn't prove for blood. A negative means there's no blood, unless the amount present is so diluted it won't cause a reaction, and TMB is quite sensitive, down to 1:10k at minimum, and I've seen papers that have it detecting at 1:1M under lab conditions."

So he would be saying a positive luminol and a positive TMB test wouldn't prove it was blood. Is there no sure test?

 

[Chris_Halkides]

when 'body meet a 'gen, diffusing through the gel

What substance would have survived a floor cleaning and only left a relatively few prints? A spilled bottle of juice that was stepped in? But why didn't anybody recall that? Maybe as Raf no one asked.

If the floor hadn't been cleaned since the prints that would seem to make relatively recent considering all the other girls having such good house cleaning skills.

There is an implicit assumption in your message that may or may not be correct, namely that there were more prints at some point. Perhaps, or perhaps only a few were made. It is odd, though, that all of the prints in the hallway have the same chirality (I think that they are all right feet, but the argument is the same if they are all left).

The older confirmatory tests formed crystals derived from heme. Newer tests usually use antibodies. The review article from 2009 by Virkler and Lednev has a discussion. Most of the confirmatory tests with which I am familiar use antibodies (basically proteins with the ability to bind just one type of molecule, called an antigen). However, the antibodies do not always target human hemoglobin:

"Blood can be identified as being of human origin by precipitin reactions with antisera specific for components of human blood. Usually this is an anti-human serum serum - that is, an antiserum to human serum. Strictly speaking, this is a test for human origin not for human blood, as serum constituents such as albumin and some globulins are found in the extra-vascular space."

"The method of choice today is the ABAcard® HemaTrace test strips manufactured by Abacus Diagnostics, Inc. Stain extract is applied to the bottom of the test strip, where any human hemoglobin present in the extract will combine with a monoclonal antihuman hemoglobin antibody."

 

[Grinder]

There is an implicit assumption in your message that may or may not be correct, namely that there were more prints at some point. Perhaps, or perhaps only a few were made. It is odd, though, that all of the prints in the hallway have the same chirality (I think that they are all right feet, but the argument is the same if they are all left).

The older confirmatory tests formed crystals derived from heme. Newer tests usually use antibodies. The review article from 2009 by Virkler and Lednev has a discussion. Most of the confirmatory tests with which I am familiar use antibodies (basically proteins with the ability to bind just one type of molecule, called an antigen). However, the antibodies do not always target human hemoglobin:

"Blood can be identified as being of human origin by precipitin reactions with antisera specific for components of human blood. Usually this is an anti-human serum serum - that is, an antiserum to human serum. Strictly speaking, this is a test for human origin not for human blood, as serum constituents such as albumin and some globulins are found in the extra-vascular space."

"The method of choice today is the ABAcard® HemaTrace test strips manufactured by Abacus Diagnostics, Inc. Stain extract is applied to the bottom of the test strip, where any human hemoglobin present in the extract will combine with a monoclonal antihuman hemoglobin antibody."

Once again " Strictly speaking, this is a test for human origin not for human blood, as serum constituents such as albumin and some globulins are found in the extra-vascular space."

I'm amazed that human blood is so hard to identify positively.

 

[Chris_Halkides]

TMB is often used as a follow-up test.

So he would be saying a positive luminol and a positive TMB test wouldn't prove it was blood. Is there no sure test?

Some of the literature suggests luminol is a little more sensitive, but the issue is complex. There has been much discussion about whether or not the luminol-positive evidence items in the Knox/Sollecito case are blood. There are six reasons to be skeptical of the notion that the greater sensitivity of luminol is the explanation for why the TMB test was negative for luminol-positive areas in this case: see this link. 5. If the only reason why TMB would be negative when luminol was positive is the lesser sensitivity of TMB relative to luminol, then there would be no reason whatsoever to follow a luminol test with a TMB. A negative TMB would not be meaningful, and a positive TMB is still not a true confirmatory test. According to the Massei report (p. 258, English translation), Sarah Gino testified about the use of TMB: “She added that, in her own experience, analyses performed with TMB on traces revealed by Luminol give about even results: 50% negative, 50% positive…” This observation suggests that the purpose of the TMB test in the field is to reduce the number of false positives, as also seems to be true based on the citations above. This interpretation is also consistent with Stefanoni’s testimony about the nature of the TMB test, as discussed in the Hellmann report: “Professor Tagliabracci, specified, without being refuted (hearing of July 18 2009, p. 174), that the tetramethylbenzedine (TMB) test is very sensitive, so much as to give a positive result even with only five red blood cells present. Dr. Stefanoni herself, moreover, clarified (preliminary hearing of October 4 2008) that, while a positive test result could be deceptive due to reactivity of the chemical [evidenziatore] with other substances, a negative result gives certainty that no blood is present.”

 

[Chris_Halkides]

constituents of whole blood

Once again " Strictly speaking, this is a test for human origin not for human blood, as serum constituents such as albumin and some globulins are found in the extra-vascular space."

I'm amazed that human blood is so hard to identify positively.

Well if you are finding human globulins and albumin, then it seems to me that you are detecting blood serum, as opposed to red blood cells. Red blood cells make up about 40% by volume of whole blood, and most of the rest is serum.

 

[acbytesla]

They both react to blood. Supposedly one is more sensitive. The luminol reacted and produced the blue glow. The ILE said they coulkd tell it was blood from the strength of the glow. They at first denied the TMB (Or is that TBM )
test had been done and came out as a negative.

Luminol also is reported to possibly destroy samples for subsequent tests. They seemed to have over-sprayed the luminol.

ETA - here's what Kaosium said "TMB gives false positives, thus a positive with TMB doesn't prove for blood. A negative means there's no blood, unless the amount present is so diluted it won't cause a reaction, and TMB is quite sensitive, down to 1:10k at minimum, and I've seen papers that have it detecting at 1:1M under lab conditions."

Luminol and TMB are both presumptive positive field tests for blood. They both react to different substances. Together they narrow the possible substances that are causing the positive reactions.

I believe the protocol is to spray an area with the luminol and then view the area under a UV light. If you notice an area that "reacts" (glows) you would then take a cotton swab with TMB and test the area to see if it reacts (changes color) If it does than you take a sample back to the lab for more definitive testing.

Perhaps Chris can further illuminate what tests are conducted in the lab that confirm that a substance is "actually blood".

So he would be saying a positive luminol and a positive TMB test wouldn't prove it was blood. Is there no sure test?

I'm pretty sure Kaosium is right but then again, I get that from my limited knowledge and recent study. A negative result eliminates the possibility that it is blood. And while Luminol does can destroy the ability to get obtain a DNA sample, It does not mitigate TMB's effectiveness.

Again, I defer to Chris. Is this right? I just noticed that Chris answered all of this...so NEVER MIND....

 

[Chris_Halkides]

luminol and DNA

Luminol can decrease the amount of DNA that one recovers, but it depends upon the formulation. My understanding from the literature is that it is often possible to get good DNA results. The presence of DNA is absolutely not a confirmatory test for blood. Luminol just needs a darkened room to give off the characteristic blue glow. Several citations that RoseMontague and I turned up showed that positive fluorescent or luminescent results for blood are often followed up by a colorimetric test (TMB or Kastle-Meyer). There is a paper on how luminol affects further presumptive tests for blood, but I cannot recall who the authors were just now.

 

[acbytesla]

with other substances, a negative result gives certainty that no blood is present.”

That should in itself ends any controversy to the luminol footprints doesn't it?

It kind of shocking to hear her make that declaration, because I'm under the impression that Stefanoni led the court to believe that the luminol footprints were the result of reacting to blood

 

[anglolawyer]

Sorry to butt in but there is the small matter of the law:

In a decision from 199536, the validation jurisprudents [=Cassation] explained the logico-inductive operation dictated by the legislature through the 2nd paragraph of Article 192 Crim. Proc. Code. The Court specified that ‚the free convincing of the court, which becomes extrinsic at the moment of the evaluation of the evidence, is the correct outcome, in a circumstantial trial, of a logico-inductive operation by which the maxim from [10] experience is positioned as the major premise, the circumstantial item [indizio] is the minor premise, and the conclusion consists of the proof of the fact under examination, which one arrives at if the circumstantial evidence is of sufficient weight [gravi], which is to say able to withstand objection and so be convincing; precise [precisi] and so be not susceptible to a different interpretation, at least as likely; and concordant [concordanti], which is to say not conflicting amongst themselves and with other definite elements.

and I trust that's all clear.

Anyway, tucked in there is that rule about circumstantial evidence having to be

- of sufficient weight (able to withstand objection)
- precise (not to be susceptible of different interpretation) and
- concordant (not conflicting with other evidence)

The luminol fails on all three counts and it would only have to fail on one to be unusable under Italian law. Negative TMB knocks it out. Hellman records that

Professor Tagliabracci, specified, without being refuted* (hearing of July 18 2009, p. 174), that the tetramethylbenzedine (TMB) test is very sensitive, so much as to give a positive result even with only five red blood cells present. Dr. Stefanoni herself ... clarified ... a negative result gives certainty that no blood is present.

Galati has nothing to say about this. It's game over on luminol and Hellman is entitled to conclude:

... on this subject: the footprints in question, in the opinion of this Court, have no evidentiary [indiziario] value against Amanda Knox.

* 'contradicted' would be a better word here.

 

[Chris_Halkides]

Thank you; that is very instructive.

 

[acbytesla]

Sorry to butt in but there is the small matter of the law: ( Galati's gobbledy gook)

and I trust that's all clear.

Good job Anglo, Reading Galati's appeal demonstrates why I hate lawyers. With the exception of present company of course. Out of curiosity Anglo, do lawyers try and write just to confuse the rest of us? Do they always have to be so ponderous??