Kate Spradley, an assistant professor at Texas State University, stands over the skeletal remains of Patty Robinson at the school’s “body farm,” officially the Forensic Anthropology Research Facility, Thurssday, Feb. 9, 2012, in San Marcos, Texas. (AP Photo/David J. Phillip)

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.”

Spradley looks over the skeletal remains of Patty Robinson at the school’s “body farm,” officially the Forensic Anthropology Research Facility, Thursday, Feb. 9, 2012, in San Marcos, Texas. Robinson donated her body for research at the school. What they’re finding at the research facility debunks some of what they and other experts believed about estimating time of death for a person whose remains are found outdoors and exposed to the environment. (AP Photo/David J. Phillip)

As for the vulture research, “we’re not a particularly squeamish lot,” he added.

The
project began after scientists noticed scavenger damage on other
bodies, an anomaly that puzzled them because the site several miles
north of campus is secured against animal intruders.

“It
didn’t fit the model of scavengers that we had seen before and what
people had written about,” said Kate Spradley, an assistant professor at
Texas State who also works on the project. “We realized we didn’t
account for something and it was vultures.”

Vultures
fly over much of the United States and are particularly abundant in the
Southwest. Two of the most common species are turkey vultures and the
more aggressive black vultures, which can exceed 2 feet in length, weigh
5 to 6 pounds and have wingspans of 5 feet.

The
initial surprise was that it took vultures 37 days to find the body.
Researchers visited the site daily and checked the camera for any
activity.

“Nothing, not even a rat,” Hamilton said.

Then
on the day after Christmas 2009, a graduate student working on another
project at the site alerted them to the vultures’ swift work on the
corpse.

“I was wondering if it ever was going to happen,” Spradley said. “We downloaded the photos, and it was stunning.”

She
and Hamilton are working with Texas State geographer Alberto Giordano
to map the area where birds dragged bones. They hope to make a
predictive model for law enforcement officers that will help determine
time of death.

Sgt.
Jim Huggins, a recently retired Texas Department of Public Safety
criminal investigator who now teaches forensic science at Baylor
University, said vultures were always something of a mystery for
investigators.

Previous research on scavenged remains focused on carnivores such as coyotes or rodents.

“This
is, as far as I’m concerned, it’s cutting edge,” he said. “No one has
ever sat down and put a pencil down and attempted this before. … This
is going to, I think, change some minds about scavengers.”

When
unidentified remains turn up, the vulture research can also be used to
help include or exclude people who have been reported missing, Spradley
said.

Hamilton
said he used to hate vultures. “But now I kind of appreciate what they
do, how they dispose of decomposing animals on landscape,” he said.
“They perform a really serious function.”

SOURCE: The Associated Press