SAN MARCOS, TEXAS (AP) - For more than five weeks, a woman’s body lay undisturbed in a secluded Texas field. Then a frenzied flock of vultures descended on the corpse and reduced it to a skeleton within hours.
But this was not a crime scene lost to nature. It was an important scientific experiment into the way human bodies decompose, and the findings are upending assumptions about decay that have been the basis of homicide cases for decades.
Experienced investigators would normally have interpreted the absence of flesh and the condition of the bones as evidence that the woman had been dead for six months, possibly even a year or more. Now a study of vultures at Texas State University is calling into question many of the benchmarks detectives have long relied on.
The time of death is critical in any murder case. It’s a key piece of evidence that influences the entire investigation, often shaping who becomes a suspect and ultimately who is convicted or exonerated.
“If you say someone did it and you say it was at least a year, could it have been two weeks instead?” said Michelle Hamilton, an assistant professor at the school’s forensic anthropology research facility. “It has larger implications than what we thought initially.”
The vulture study, conducted on 26 acres near the south-central Texas campus, stemmed from previous studies that used dead pigs, which decompose much like humans. Scientists set up a motion-sensing camera that captured the vultures jumping up and down on the woman’s body, breaking some of her ribs, which investigators could also misinterpret as trauma suffered during a beating.
Researchers are monitoring a half-dozen other corpses in various stages of decomposition, and they have a list of about 100 people prepared to donate their bodies to the project, which the school says is the first of its kind to study vultures.
“Now that we have this facility and a group of people willing to donate themselves to science like this, we can actually kind of do what needs to be done, because pigs and humans aren’t equal,” Hamilton said.
The forensic center opened in 2008, as did a similar facility at Sam Houston State University in Huntsville, making Texas home to two of the nation’s five “body farms.”
At the farms, forensic pathologists observe the decomposition process in natural surroundings to see how corpses react to sun and shade, whether they decay differently on the surface or below ground and what sort of creatures _ from large to microscopic _ are involved.
Only in recent years has academic literature tried to establish formulas for death time based on stages of decomposition and environmental factors such as temperature conditions where the body was found.
The vulture research has drawn interest from homicide investigators, including Pam McInnis, president of the Southwestern Association of Forensic Scientists and director of the Pasadena Police Crime Lab in suburban Houston. She said the ability to account for vultures would “significantly” help investigators who already use insects and their life cycles to estimate time of death.
The body in the vulture study was that of Patty Robinson, an Austin woman who died of breast cancer in 2009 at age 72. She donated her remains to research, and they were placed in a five-acre fenced area.
Her son, James, said the Texas State research seemed like a worthy project.
She’d be delighted “if she could come back and see what she’s been doing,” he said. “All of us are pretty passionate about knowing the truth.”