Footprint identification test

[Dan O.]

This is evidence from a murder investigation. The center stain in the victims blood was found on a bathmat in the victims home where the victim had been brutally murdered. Reference prints in black and white are shown for two suspects. All prints are to the same scale.

Spoilers will undoubtably be posted in the thread so please complete the poll before reading past the OP.


ETA: Discussion of the case is strictly forbidden in this thread. Please limit discussions to the questions of the poll and identifications of footprints.

 

[Professor Yaffle]

While waiting for the poll to appear, I wonder whether there will be an option for "What you asking me for? - I'm not a forensic expert".

 

[Dan O.]

Maybe we will hear from forensics experts that will explain what we are missing. But while you are here, can you fix the title on the pole? It appears to have copied the image instead of the title from the post.

 

[maggot9779]

They all look different to me. But i'm no expert.

 

[EvilSmurf]

That really high arch seems consistent with the sample on the right.

 

[Sideroxylon]

That really high arch seems consistent with the sample on the right.

Maybe not even a high arch, perhaps due to the way the blood was spread on the foot.

 

[casebro]

Strange looking feet, with all that 'ball' extending out past the little toe. Are the two suspects related?

Or maybe the strange shape is caused by the surface stepped on to make the image?

Obviously the two samples were done on something with waaay better resolution, like standing on a scanner? I'd like to see the shapes done by the feet to a matching bath mat. Oh, also, what accounts for the foot print even showing on the mat? Wet ? Or just squooshed by the body weight? Forensic evidence ought to try to match the circumstance.

 

[Professor Yaffle]

Maybe we will hear from forensics experts that will explain what we are missing. But while you are here, can you fix the title on the pole? It appears to have copied the image instead of the title from the post.

I can't find how to edit polls, but I'll report the OP and ask if any of the other mods know how.

I guess I just don't see the point of a poll. You will get a consensus on which suspect's footprint looks superficially most similar from a layperson's perspective, but I'm sure experts rely on other things that we, as non-experts haven't a clue about. So I don't know why you would be interested in the outcome of the poll. Science isn't a popularity contest.

 

[drkitten]

This is evidence from a murder investigation. The center stain in the victims blood was found on a bathmat in the victims home where the victim had been brutally murdered. Reference prints in black and white are shown for two suspects. All prints are to the same scale.

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=597&pictureid=3970[/qimg]


Spoilers will undoubtably be posted in the thread so please complete the poll before reading past the OP.

Given the differences between blood-on-bathmat (which is designed to be quite thick and quite spongy) and ink-on-paper or ink-on-scanner, a simple visual comparison of the sort proposed in the OP is likely to be quite misleading.

As a simple example, the "elongated" big toe we see in the right print simply means that the rightmost foot has the phalanges slightly lower than the foot on the left. But precisely because a bathmat is soft and spongy, the leftmost foot would have sunk further into it, which might have been enough to leave traces of the the phalange of the big toe.

It's also not clear what kind of color enhancement has been performed on the stain, which of course can shift the image to anything you like (faces on Mars, anyone?).

That said, I find the narrowness of the arch in the bloodstain as well as the apparent pattern of weight distribution to be more consistent with the right foot than the left. But I would hesitate to go to court with that suspicion; I'd hesitate even to sign a deposition to that effect.

 

[Dinwar]

I went with the foot on the left, because the top part (where most of the markers I can see are) of the bloody footprint is missing the large dip between the big toe and the next toe that the right one has. There's also a few other things about the general shape that indicate to me that it's the left one.

That said, I don't think that this test is very relevant or useful. The problem is that the test prints are made on a flat sheet, and taken either with ink (if it's old-style) or electronically (got my fingerprints taken for a security access badge that one recently). The bloody footprint is on a soft surface with high porosity (basically a bunch of holes held together by fibers) and with a higher-viscosity fluid that changes over time (blood drops, in my experience, change shape slightly as they dry; on a side note, explaining to your professor why his $50,000 piece of machinery has blood spots on it takes some doing). You're only going to get the grossest approximation here--shoe size (roughly), a general shape, maybe some huge markers showing the difference. Plus, if the person who made the print was moving it'd alter the shape significantly, certainly enough to cover up the markers available to us.

In all, I'm leaning to the left but certainly not enough to convict anyone.

 

[Dr.Sid]

I like how the questions are well defined. Unfortunately at the moment the pool is on main page together with the picture and whole layout is completely broken.

 

[Dan O.]

There is some valid criticism concerning the way the reference prints were obtained. Unfortunately, this is the way the investigators chose to make the comparison that was presented in court.

My interest here is to collect an impression from an unbiased group and compare these results with the apparently biased perception of those that have staked a side in the case.

Something else that could be discussed, does my presentation of this poll show a bias? Unfortunately due to technical limitations I couldn't randomize the left/right positions but did try to throw in enough non answers to weed out the non-responders.

 

[Dan O.]

They all look different to me. But i'm no expert.

Thanks, I actually think the right and left prints have more in common than the one in the center but forgot to put that option in the poll.

I see you've been lurking for quite some time. Welcome to the interactive side of JREF.

 

[TraneWreck]

Based on the big toe and the arch it looks like the one on the right to me, but I suppose this is a set up to point out a non-obvious answer.

As a complete novice on this subject, I'm guessing that the pressure, what the footprint was made in, the angle of the foot, and all manner of other factors could make the one that isn't immediately similar the correct answer.

 

[maggot9779]

Thanks, I actually think the right and left prints have more in common than the one in the center but forgot to put that option in the poll.

I see you've been lurking for quite some time. Welcome to the interactive side of JREF.

Thanks

I've looked more closely and I think you are correct. The main things that threw me off were the toe size and the creases.

 

[Pope130]

My unprofessional opinion is that I don't know. Both the reference prints have some points in common with the crime scene print, but to my eye have significant differences such that I would reject both of them. If it turns out one of them is from the same foot it wouldn't surprise me. Differences in the process of blood deposited on a bath mat and ink on a card could well account for the significant differences I see in the prints.

Robert

 

[Weak Kitten]

Though it seems to match up with the foot on the right more than the one on the left, the foot on the left is either a very bad print or a very odd foot. Without the position of the small toes and some sort of partial on the actual wrinkle patterns of the foot I would consider this to be completely inconclusive. About the only thing it proves in this condition is that someone stepped in the blood.

 

[Fnord]

Is this another Bigfoot thread?

 

[Dan O.]

It is refreshing to see that the unbiased opinion is predominantly that there isn't enough information to form an opinion.

I see that a helpful tagger has marked this thread with the tag "Amanda Knox". Yes, this is evidence in that multivolume epic doing cartwheels over a love/murder quadrangle which you can read more about here and here (assuming you are into that kind of mental abuse). I'll need to remove that tag until the poll closes so it doesn't bias the result.

 

[Prometheus]

They all appear to have been produced by descendents of some sort of lobe finned fish, or other quadruped. Beyond that, I do not have the appropriate expertise to form a confident judgement.