Thursday, September 04, 2008

Newsflash! Handwriting Experts Differ.

found by troym;by blogger jgl

I don't mean to be too hard on handwriting experts, i just think it is too tough of an art to qualify as "scientific evidence". This is a somewhat lame example, but it sounds like the author of this news story hired 3 experts to look at a cold case. They disagreed.

The experts contacted for this story examined a letter and a receipt known to have been written by Linda Sohus prior to her disappearance... ...They also scrutinized a postcard mailed from France after the couple vanished from their Lorain Road home in February 1985.

Two of the examiners said the postcard was not written by Linda Sohus. But a third said she is nearly certain it was written by Linda.

In defense of 2 of the analysts, the one with the differing opinion also practices graphology.

"Many of the letters butt up against each other, showing a lack of clear social boundaries," Lowe wrote. "The bowed t-bars suggest that she could easily be talked into or out of doing something."


Tuesday, September 02, 2008

Caylee's Body - Forensic Proof?

by blogger jgl

I had half an ear on this last night, and was a bit suspicious of what i heard. The context was that police have "forensic evidence" that "formally indicates" Caylee was dead. I was wondering what the heck this meant. As far as i can tell, they found a hair that they can "prove" was from a decomposing body.

The sheriff's office in Orange County, Florida, now says that lab tests have confirmed that a decomposing body had been in the trunk of a car driven by Casey Anthony...

...Forensics tests confirmed there had been a decomposing body in the car, the statement said. Detectives disclosed at a July hearing the trunk contained hair samples appearing to belong to Caylee, a strong odor and suspicious stain that glowed under black light.

A couple things...

First off, this video is humorous as Nancy and some guy debate whether there is new "DNA evidence" or "scientific evidence". (embed video might not work in firefox - follow above link)

It sort of highlights how the media can occasionally bypass the meaning of evidence and just parade around a fact as true if "forensics" supports it. Also, in case you don't know what DNA stands for, Nancy's got you covered.

Second, let's look at this hair evidence. Here's a video about the analysis by people "who are known to be experts on this stuff".

I'm not overly confident in the conclusion. I *think* the analysis completed at the body farm is based on a 2001 article (Linch, CA, Prahlow JA. Postmortem Microscopic Changes Observed at the Human Head Hair Proximal End. J Forensic Sci 2001;46(1):15-20). This article demonstrates that these postmortem bands are sometimes found on decomposed hair, but not all the time. More importantly, there is not a lot of documentation on whether antemortem hairs could sometimes exhibit this banding. Of course, proving that antemortem hairs could *never* look like postmortem hairs would be a tall order.

I'm wondering if any blind proficiency tests of this type have ever been administered to hair analysts. Microscopy is tough. Can they get it right 100% of the time? I also haven't read who at the body farm was analyzing the hairs. Maybe it is author Linch and he's done a lot more work on this since his 2001 study.

Hopefully the media and investigators aren't jumping the gun on this "forensic proof" that a dead body was in the trunk. It sounds like a safe bet. From what i am reading, the trunk smelled bad and cadaver dogs hit on it (i think - i've been lazily following this story).

As for the DNA that may or may not be there... here's a prediction. They will find Caylee's hair in the trunk of her mom's car. Even if the mom turns out to be innocent. Hair gets all over the place. I wouldn't be surprised if my hair was all over the trunk of my parent's cars when i was a kid. Even worse, they'll do mtDNA and find hair that *might* have been from Caylee (gasp!) or from her mother (sigh).

Two final thoughts... #1 why do they have to dress up Nancy's guest hosts like Nancy herself? #2 are they pronouncing "hair" as "air"?

Clarification: They took both "hair and "air" samples from the trunk to test for a decomposing body. This is turning into a Dr. Seuss story. what are they testing the air for... i'll have to see what research has been doen on this.