http://www.skepticaljuror.com/search/label/Preston%20Hughes%20III

Tuesday, June 12, 2012


The Case of Preston Hughes III: Marcell's Neck



Color me surprised.

Again.


I should have realized this earlier, even as I challenged you with Brain Teaser #2, the one in which I provided autopsy descriptions of Shandra and Marcell's neck wounds. But you know what they always say: "Blogger, challenge thyself."




In Shandra's Neck, after inserting Preston's knife into the eponymous neck, I concluded that the wound path had to be either front-to-back or side-to-side. The knife could not have been inserted obliquely. This prompted me to send away for the autopsy reports, which the Harris County Institute of Forensic Sciences provided at modest cost and reasonable speed. Shandra's autopsy report made clear that the wound path through Shandra's neck was from front-to-back, slightly to the right, and slightly up.




The wound path through Marcell's neck was more complicated. It was from front-to-back, slightly to the left, and upwards. Notice the lack of "slightly" before the word "upwards". Marcell's injury was definitely three-dimensional, not approximately two-dimensional as was Shandra's.




Marcell's autopsy report provided enough information to estimate the vertical angle of his neck wound. The entrance wound was 7 inches from the top of the head while the exit would was only 4 inches from the top. In other words, the wound path climbed 3 inches from front to back, assuming the victim was in the anatomical position.




The autopsy report also made clear that the wound path distance between the entry and exit points was 4 inches. Sounds like trig time to me. (For the mathematically faint-of-heart, you may want to look away.) The sine of the angle is the rise divided by the hypotenuse. The rise is 3 inches and the hypotenuse is 4 inches, so the sine of the angle is 0.75. The arcsine of 0.75 is 48.6 degrees. Yikes!




Okay, you can look back. The knife traveled upwards through Marcell's neck at approximately a 45 degree angle. Yikes!




I attempted to use Google Sketchup (now Trimble Sketchup) to insert Preston's knife into Marcell's neck at a 45 degree upward angle. As it turns out, that's not as easy as it sounds. I was making my third run at the problem this morning when I realized I didn't need a 3-D model to tell the story. The mismatch between the wound and Preston's knife is so egregious that a 2-D model, such as I used for Shandra's neck, will tell the story just fine.




Here we go. I present below Preston's knife inserted into Marcell's neck.

Continue:
http://www.skepticaljuror.com/search/label/Preston%20Hughes%20III