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Continuation - Discussion of the Amanda Knox case

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With the knife, I think it's fairly well-agreed that somehow a tiny piece of Meredith's DNA was recovered from the blade. I don't think that this is being contested, so a match is not surprising in the least. What is being contested is how that tiny piece of DNA came to be on the blade of the knife.

I think that is a fair point. DNA tests from a large sample are probably reliable, but when tests are done on tiny samples, or of poor quality, they can be highly misleading. It may be surprising to those have faith in the CSI effect, but DNA tests are one of those things that starts being used, and then becomes ever more sensitive, but the reliability of the tests are not verified but just assumed. The New Scientist magazine recently published articles exposing this problems, and some DNA tests have been challenged in court.

AFAIK only the knife from Sollecitos kitchen was tested. Would Meredith's DNA also been found on trace amount on other objects? Since Amanda regularly went back and forth, some contamination does not seem surprising. Perhaps that knife had also been back and forth.

It is also not inconceivable that Sollecito had handled the bra clasp under other circumstances, since he was a visitor at the cottage.. I'm not suggested anything untoward, but clothing gets left lying around or mixed up.
 
Who can say? Some material lacking DNA? This could be red blood cells below the threshold of the blood test used. I guess if bleach was used it could be the debris left over from the action of the bleach on the cells.

You seem very certain on this. How much material would there need to be for it to be visible?


So, what do you think was in the scratch?

A presumptive test for blood only requires a tiny number of red blood cells (erythrocytes) to give a positive - as few as 50 erythrocytes or a blood/water dilution of 1/100,000. Erythrocytes are truly tiny - each one measures only around 7 microns (0.007mm) in diameter, so 50 of them would be invisible to the naked eye.

If it were some sort of bleach residue, then there's no conceivable reason to suggest that active bleach would not have destroyed any skin cell DNA.

Personally, I think there was nothing in the scratch of any biological value. I think it's highly likely that either the collection swab or the lab equipment had become contaminated with a miniscule amount of Meredith's DNA from elsewhere in the lab. I think that the lack of proper procedures and protocols in Stefanoni's lab made such contamination a very real possibility. I'd like to believe that accidental contamination is a far higher probability than deliberate planting (by anyone in the evidence custody chain).
 
I think that is a fair point. DNA tests from a large sample are probably reliable, but when tests are done on tiny samples, or of poor quality, they can be highly misleading. It may be surprising to those have faith in the CSI effect, but DNA tests are one of those things that starts being used, and then becomes ever more sensitive, but the reliability of the tests are not verified but just assumed. The New Scientist magazine recently published articles exposing this problems, and some DNA tests have been challenged in court.

AFAIK only the knife from Sollecitos kitchen was tested. Would Meredith's DNA also been found on trace amount on other objects? Since Amanda regularly went back and forth, some contamination does not seem surprising. Perhaps that knife had also been back and forth.
Do you mean that Raffaele or Amanda either touch Meredith, or touch something she touched and then go home, touching a bunch of other stuff and then touch something at Raffaele's transferring to that a whole bunch of their own DNA, trace DNA from whatever else they touched and a tiny amount of Meredith's DNA that hadn't been transferred to any of the other things they touched? If that is the case there would surely be a lot more DNA from Raffaele's cleaner, other students, and so on. You'd be doing well to pick out two clean samples of Meredith's DNA, even at stupidly low level, surely?

It is also not inconceivable that Sollecito had handled the bra clasp under other circumstances, since he was a visitor at the cottage.. I'm not suggested anything untoward, but clothing gets left lying around or mixed up.
Raffaele doesn't claim to have touched it. It could be another forgotten bit of alibi I guess.
 
Sure, signs of smearing, no signs of smearing due to cleanup that I can see. It would surprise me not to find some occasional smearing in footprints like these.

I believe that even if there was clean up, it does not automatically implicate Knox or Sollecito. Someone posted a scenario where Rudy entered the cottage (possibly broke in) with some accomplices, looking for valuables or drugs.

Rudy would not have wanted to be recognized, so perhaps he initially provided local knowledge but nevertheless became involved. Meanwhile Meredith is terrorized and things go too far. Rudy is now worried he is implicated in a murder, since he is a known visitor to the cottage. A clean up operation is attempted to remove more obvious traces of evidence, and the break in staged. The intention not being to frame the occupants, but a hasty attempt to cover up their involvement. Rudy's admissions of being at the cottage but not directly involved may be as close to the truth he can get with ratting out his accomplices.

Later, the hapless Knox and Sollecito wander into the crime scene without realising it. Shock, confusion, substance abuse and a coldness of character cause them to make erratic statements which implicate others or themselves.
 
Do you mean that Raffaele or Amanda either touch Meredith, or touch something she touched and then go home, touching a bunch of other stuff and then touch something at Raffaele's transferring to that a whole bunch of their own DNA, trace DNA from whatever else they touched and a tiny amount of Meredith's DNA that hadn't been transferred to any of the other things they touched? If that is the case there would surely be a lot more DNA from Raffaele's cleaner, other students, and so on. You'd be doing well to pick out two clean samples of Meredith's DNA, even at stupidly low level, surely?


Raffaele doesn't claim to have touched it. It could be another forgotten bit of alibi I guess.

The fact that there are other unidentified traces on the bra clasp argues for contamination. The alternative is that several other people handled her bra clasp. How likely is that?
 
Personally, I think there was nothing in the scratch of any biological value. I think it's highly likely that either the collection swab or the lab equipment had become contaminated with a miniscule amount of Meredith's DNA from elsewhere in the lab. I think that the lack of proper procedures and protocols in Stefanoni's lab made such contamination a very real possibility. I'd like to believe that accidental contamination is a far higher probability than deliberate planting (by anyone in the evidence custody chain).

There was an article yesterday in Corriere dell'Umbria (which seems to have disappeared now, though it was posted on PMF so I didn't imagine it) which stated that if the independent experts couldn't examine the samples directly they had to look at Stefanoni's work to determine whether her methodology and interpretation of the results were "correct, reliable, and in line with the parameters established by the international scientific community". I think the bolded part is very significant, especially in relation to the knife - I can't see any way it will survive the independent review with those criteria (to the point that discussing it almost seems futile). The results on the bra clasp will be interesting, particularly since the new experts can carry out their own tests on it.
 
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For capealadin

I am rushing out the door so only have time for a quick link; more later. Judge Micheli ruled that any of the information Rudy claimed to know firsthand could have come from news reports.

http://www.penale.it/page.asp?mode=1&IDPag=750

Look for references to TV, televisione, televisioni, and stampa (press).
 
A presumptive test for blood only requires a tiny number of red blood cells (erythrocytes) to give a positive
Are we talking about the blood test used here, or some generic one? They differ by orders of magnitude. As I recall this is on the sensitive end.

- as few as 50 erythrocytes or a blood/water dilution of 1/100,000. Erythrocytes are truly tiny - each one measures only around 7 microns (0.007mm) in diameter, so 50 of them would be invisible to the naked eye.
So by this calculation she might have been able to see a spot composed entirely of red blood cells and yet, when the sample was divided to test for DNA and blood, no blood would have been detected? Presumably there is something else in it other than red blood cells for the DNA result to come back as it did. Is the maths wrong, or have I misunderstood? I think this was the result the first time it was calculated on the thread.

If it were some sort of bleach residue, then there's no conceivable reason to suggest that active bleach would not have destroyed any skin cell DNA.
At the margins of material destroyed by bleach (in a hypothetical world where this is what has happened), wouldn't you have damaged cells and intact cells?

Personally, I think there was nothing in the scratch of any biological value. I think it's highly likely that either the collection swab or the lab equipment had become contaminated with a miniscule amount of Meredith's DNA from elsewhere in the lab. I think that the lack of proper procedures and protocols in Stefanoni's lab made such contamination a very real possibility. I'd like to believe that accidental contamination is a far higher probability than deliberate planting (by anyone in the evidence custody chain).
Could be. I'm still waiting for more information on all of this. Hopefully if the defence decide to go with this line of thinking more information will be made public.
 
The fact that there are other unidentified traces on the bra clasp argues for contamination. The alternative is that several other people handled her bra clasp. How likely is that?
Are they at the same level as is claimed for Raffaele's DNA?
 
I believe that even if there was clean up, it does not automatically implicate Knox or Sollecito. Someone posted a scenario where Rudy entered the cottage (possibly broke in) with some accomplices, looking for valuables or drugs.

Rudy would not have wanted to be recognized, so perhaps he initially provided local knowledge but nevertheless became involved. Meanwhile Meredith is terrorized and things go too far. Rudy is now worried he is implicated in a murder, since he is a known visitor to the cottage. A clean up operation is attempted to remove more obvious traces of evidence, and the break in staged. The intention not being to frame the occupants, but a hasty attempt to cover up their involvement. Rudy's admissions of being at the cottage but not directly involved may be as close to the truth he can get with ratting out his accomplices.

Later, the hapless Knox and Sollecito wander into the crime scene without realising it. Shock, confusion, substance abuse and a coldness of character cause them to make erratic statements which implicate others or themselves.

My guess is that Rudy broke in through Filomena's window. Started searching around her belongings and his nerves caused him to need a bathroom. Meredith came in while he was on the toilet, locking the door behind her with her keys. He snuck up on her in her bedroom, murdered and sexually assaulted her, cleaned up quickly in the bathroom, went back to her bedroom and took her cell phones, keys, and money and then left out the front door, locking both the bedroom door and front door on his way out.
 
It should be obvious to any intelligent and critical thinking person, that the left print shows signs of smearing in the pic http://www.tgcom.mediaset.it/fotogallery/fotogallery3634.shtml?2, ironic that it was Katody Matrass first impression as well. The luminol around the left print also matches the quote on Bluestar site "Visible blood traces are often washed off but reappear larger when reacting with BLUESTAR® FORENSIC. If rinsing dilutes blood, it also widens the trace, making it easier to discover" which is evident in all the pictures posted including those from the "A very messy clean up" gallery.

To me there was definite attempt to clean the left print, while the right one remains mostly untouched, which may have been because it was not visible to the eye without luminol so there was no attempt to clean it in my opinion.

As for my sweater reference it was back in the old thread though I probably now agree with katy_did assessment of photographers feet in view, but the pictures were familiar to me so when you described the exact criteria that you now deny, it was not hard to find them.

I noticed slight smearing, possibly because of shuffling. Definitely not because of cleanup. Cleaning wouldn't left a discernible footprint outline, but large "painting" swipes or just a uniformly glowing area. Compare the photos from the "messy" gallery.
Reaction in the corridor looks also very weak, compared to the demo.

BTW It's hard to imagine what exactly was cleaned in the corridor if the cleaning produced no cleaning marks but left unscathed luminol detectable footprints and a path of bloody shoeprints visible with naked eye.
 
on the fence

There was an article yesterday in Corriere dell'Umbria (which seems to have disappeared now, though it was posted on PMF so I didn't imagine it) which stated that if the independent experts couldn't examine the samples directly they had to look at Stefanoni's work to determine whether her methodology and interpretation of the results were "correct, reliable, and in line with the parameters established by the international scientific community". I think the bolded part is very significant, especially in relation to the knife - I can't see any way it will survive the independent review (to the point that discussing it almost seems futile). The results on the bra clasp will be interesting, particularly since the new experts can carry out their own tests on it.

katy_did,

If they ask for the electronic data files, then I will believe that they are serious. Until then, I remain on the fence.
 
Are they at the same level as is claimed for Raffaele's DNA?


The unidentified profiles are smaller than Raffaele's, but all in the LCN range including Raffaele's (as pointed out in his appeal, his portion of that sample falls into the definition of LCN). Meredith's is the only portion big enough to be excluded as LCN.
 
Do you mean that Raffaele or Amanda either touch Meredith, or touch something she touched and then go home, touching a bunch of other stuff and then touch something at Raffaele's transferring to that a whole bunch of their own DNA, trace DNA from whatever else they touched and a tiny amount of Meredith's DNA that hadn't been transferred to any of the other things they touched? If that is the case there would surely be a lot more DNA from Raffaele's cleaner, other students, and so on. You'd be doing well to pick out two clean samples of Meredith's DNA, even at stupidly low level, surely?

Well I don't know, I am not a DNA expert. If germs get spread by contact, why not tiny samples of skin cells... that would not necessarily mean that DNA would be spread everywhere, it would still be in discrete clumps. If the swab happens to pick up a clump, bingo, positive test. The very sensitivity of the DNA test is in itself a problem with the test.

I do know at low levels DNA tests required careful interpretation. If I was on the jury, I would be asking "have the prosecution proved that that DNA could only be there by direct contact, and have the prosecution proved that the knife was used in the murder?"

Did they test for the cleaner, other students? Were samples found but not presented as not being relevant? The problem is that with two small samples found among hundreds of possible locations where there could be a reasonable explanation, it could be a case of keep testing and eventually they will find something by coincidence.

If it was found belonging to people with absolutely no other connection with the victim then it would be a lot more damning. The fact that it was found belonging to someone who is a close friend and frequent visitor introduces an element of doubt, IMO.
 
The unidentified profiles are smaller than Raffaele's, but all in the LCN range including Raffaele's (as pointed out in his appeal, his portion of that sample falls into the definition of LCN). Meredith's is the only portion big enough to be excluded as LCN.
I don't see that being in or outside the LCN range is the best way of categorizing this. LCN is obviously related to testing techniques. Presumably some judgement can be made, based on the quantity involved, as to the likelihood of it having come from direct contact?
 
I am not going to bore everyone here with what has being discussed at length. If ou choose to believe that Rudy was lying about there being a lot of blood in the bathroom and corridor, so be it. I don't understand why he would lie about something like that, if, as you say, there was no cleanup. He admits to being there. He has nothing to gain, in saying that.

As I have also often pointed out. Why would rudy lie about the time he arrived or the time he left.
 
Do you mean that Raffaele or Amanda either touch Meredith, or touch something she touched and then go home, touching a bunch of other stuff and then touch something at Raffaele's transferring to that a whole bunch of their own DNA, trace DNA from whatever else they touched and a tiny amount of Meredith's DNA that hadn't been transferred to any of the other things they touched? If that is the case there would surely be a lot more DNA from Raffaele's cleaner, other students, and so on. You'd be doing well to pick out two clean samples of Meredith's DNA, even at stupidly low level, surely?

If lots of samples from his flat were tested in a way the knife was we would get lots of various individuals' DNA. I think it's quite possible we would get also a complete history of DNA samples handled by Stafanoni's lab :)



Raffaele doesn't claim to have touched it. It could be another forgotten bit of alibi I guess.

Considering that he was no stranger to the girls house and taking into account the mess ILE made there before rediscovering the clasp I wouldn't convict him on such evidence.
 
The unidentified profiles are smaller than Raffaele's, but all in the LCN range including Raffaele's (as pointed out in his appeal, his portion of that sample falls into the definition of LCN). Meredith's is the only portion big enough to be excluded as LCN.

Were there actual unidentified profiles or was it perhaps possible partial profiles based on hypothesis by Professor Tagliabracci?
 
I don't see that being in or outside the LCN range is the best way of categorizing this. LCN is obviously related to testing techniques. Presumably some judgement can be made, based on the quantity involved, as to the likelihood of it having come from direct contact?

Sure, there was plenty of direct contact with the dirty gloves the lab techs were wearing in the bra clasp collection video, then it was dropped on the floor in direct contact with an area three of them had already stepped on in their little white booties (which were put on in the living room, IIRC, and then of course they walked through the living room and hall picking up who knows whose DNA on the bottom of those booties already). LOL.

The potential for contamination just from that video is enough to cast this evidence in doubt even before you consider how it moved across Meredith's floor in the 44 days it was left there to an area of a pile of junk and clothes by the desk also containing who knows whose DNA.
 
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