http://www.latimes.com/news/local/la-me-sanmarino26-2008aug26,0,4359902.story
Ground-penetrating radar to be used at missing couple's San Marino home
'It would be like digging up the yard ... you can see everything without
any damage,' says a Denver expert who will aide the sheriff's
investigation. Meanwhile, Clark Rockefeller interview airs on NBC
By Molly Hennessy-Fiske and Richard Winton
Los Angeles Times Staff Writer
August 26, 2008
Investigators are planning to use ground-penetrating radar in coming days
to search for human remains and other evidence at a San Marino home that is
at the center of a bizarre international mystery.
A young couple who lived at the home vanished in 1985, and nine years
later, the remains of an unidentified man were found buried in the
backyard. The cold case has generated new interest with the Los Angeles
County Sheriff's Department naming a Boston man, Clark Rockefeller, as a
"person of interest" in the couple's disappearance and suspected deaths.
Los Angeles County sheriff's homicide detectives are bringing in a Denver,
Colo., geophysicist to examine the property where Jonathan and Linda Sohus
lived, said Capt. Dave Smith, who leads the department's homicide bureau.
Smith said the technology could be used later this week or early next week,
and the examination may take a day or could last several days. One reason
for using radar is that investigators do not want to disturb the grounds of
the house, he said, where the new owners have been mobbed by national media.
"Hopefully we can see something that will allow us to concentrate on one
particular area" to dig, Smith said.
Investigators last staged a massive dig at the yard in 1994, after new
residents uncovered bones while digging a backyard swimming pool. The
bones, later identified as those of a small-framed man, had been separated
into three parts and wrapped in plastic. Investigators also discovered
bloodstains in a guest house on the property. While the remains have not
been formally identified, detectives suspect they are those of Jonathan Sohus.
Smith said ground-penetrating radar has not been used on the yard before,
likely because the technology did not exist in 1994. Experts say more
recent advances in associated computer software, also used for medical
imaging such as X-rays and CAT scans, have made it more popular.
Experts say investigators have successfully used ground-penetrating radar
to unearth remains in other cold cases.
Lawrence B. Conyers, a University of Denver professor of anthropology who
has used ground radar on the La Brea Tar Pits and to aide homicide
detectives in a San Luis Obispo cold case, said it can find long-buried
bones several feet underground.
The radar, similar to weather radar or navigational radar used on ships,
creates a picture of the underground landscape by bouncing electronic
pulses off objects. Investigators can search a 50-by-50-meter area in a
single day, he said.
"What you get is really what you see if you dug a trench with a backhoe,"
Conyers said, calling the radar images "a vertical slice of the ground."
Conyers said the radar can locate even long-buried objects--he used it to
reveal the details of a buried ancient Roman temple in Petra, Jordan.
The technology also has become more advanced in recent years, he said. Once
experts scan an area, they can use computer software to turn those images
into subterranean maps. The ground radar he used at the tar pits in 2005
was a lawn mower-like device wired to a flat-screen monitor 20 feet away
that displayed the outline of objects up to six feet underground. Now,
Conyers said, the device is the size of a lunch box, capable of penetrating
the floors of buildings, and software can generate three-dimensional videos
of underground images.
"Concrete does not matter," he said. "In this case, it would be like
digging up the yard. But thanks to this technology, you can see everything
without any damage."
But Conyers and other forensic experts cautioned that the technology is
best used to find a shaft or grave where remains were buried, and cannot
show whether the remains are human.
During the 1994 dig at the Sohus home, investigators found a set of remains
they at first believed were human, but which they later determined were animal.
"It's not going to show you a skeleton, of course, but it may show you an
anomaly, some place of disturbance that you may want to check out," said
Nicholas Herrmann, an assistant professor of anthropology at Mississippi
State University who worked with ground-penetrating radar to locate
unmarked graves and to research decomposition at the University of
Tennessee's acclaimed "Body Farm" facility.
Herrmann said that depending on the soil density in the yard, investigators
could also use other underground imaging techniques, such as soil
resistance, to locate places where the ground has been disturbed.
According to a map produced by the Natural Resources Conservation Service,
much of Los Angeles County soil is highly suitable for ground-penetrating
radar imaging.
Property records show the lot on Lorain Road is 13,924 square feet,
including a 4,015-square foot house that neighbors say was largely rebuilt
after the Sohus couple disappeared.
The Sohus investigation drew national attention earlier this month when
detectives said Rockefeller, who was being held in Boston on unrelated
kidnapping charges, was wanted for questioning in the disappearance and
suspected killings of Linda, 28, and Jonathan Sohus, 26.
Authorities believe Rockefeller, then known as Christopher Chichester,
lived in the Sohus' guesthouse at the time the couple disappeared.
Rockefeller's attorney confirmed in an interview with The Times that his
client lived in the guesthouse. But he stressed that Rockefeller barely
knew the couple and had nothing to do with their disappearance.
Rockefeller spoke publicly for the first time last week in interviews with
the Boston Globe and NBC's "Today" show.
The Globe reported that when Rockefeller was asked about his memories of
John and Linda Sohus, he fell silent and smiled tightly, as his attorney
told reporters to "move on to something else."
During the "Today" interview, which aired this morning and is expected to
continue Tuesday morning, Rockefeller said he did not remember his early
life and that he was told he was a Rockefeller by someone he cannot name.
He said he was supported during his years in Boston by his wife Sandra
Boss, a high-powered and high-salaried consultant whom he met while
role-playing the murder mystery board game "Clue."
================================
George Antunes, Political Science Dept
University of Houston; Houston, TX 77204
Voice: 713-743-3923 Fax: 713-743-3927
antunes at uh dot edu
