Caylee Anthony and Casey Anthony
Orlando Sentinel/MCT/Landov; Orlando Sentinel/MCT/Getty
06/04/2011 at 03:00 PM EDT
Throughout the Casey Anthony murder trial, senior writer Michelle Tauber will be providing exclusive behind-the-scenes impressions and insights from PEOPLE's up-close courtroom seat
It wasn't a grieving grandmother
, a revealing ex-boyfriend or a volatile jailhouse video
that captivated the Casey Anthony jury on Saturday.
It was Q-12, deemed to be a single strand
of a lost little girl's hair. And it was damning.
Q-12 is the clinical, methodical tag given to a strand of hair that FBI microscopic analyst Karen Korsburg Lowe positively identified as “similar” to hair pulled from 2-year-old Caylee Anthony’s hair brush. (DNA testing is the only way to confirm the match, Lowe said, and no DNA
evidence was admitted Saturday. But Lowe also noted that the hair was "dissimilar" to a sample taken from Caylee's mother Casey.)
Light-to-medium brown, 9 inches long, the single strand was the focus of testimony on Saturday in Casey’s first-degree murder trial
Lowe testified in emotionless, scientific terms about the piece of hair found in the trunk of Casey's Pontiac Sunfire that showed signs of "post-mortem banding."
Q-12 “has a darkened band at the root portion of the hair ... this is consistent with apparent decomposition," Lowe said.
Q-12, a strand of hair the prosecution alleges was Caylee’s – baby hair, the kind that's meant to be tucked lovingly into a memory book – had instead been found rotting in the trunk of a car.
The nitty-gritty science was dry, but the jury paid close attention.
Casey, meanwhile, listened impassively to the testimony about her little girl
's locks, her own long, dark brown hair now stretching nearly all the way down her back.