Some View Devices As An Invasion Of Privacy

THERMAL IMAGING RAISES LAW ENFORCEMENT QUESTIONS

Criminal defense lawyers, civil libertarians and others contend the
equipment infringes on Fourth Amendment rights.
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In late November, Roanoke County police got a tip that some residents in
Southeast Roanoke County were growing marijuana in their home.

The informant was specific: 20 plants could be found in the basement; on
weekends, a large amount of traffic frequented the home on a wooded
cul-de-sac.

But the tipster's information was several months old, and police didn't
think it was enough to convince a magistrate to issue a search warrant. So
they checked with the power company to see if the homeowners' electric
bills were abnormally high -- possible evidence of an indoor
marijuana-growing operation.

When the homeowners' electric bills didn't raise a red flag, police didn't
give up. Instead, they brought in a "thermal imager," a controversial,
high-tech device that measures heat -- the use of which has been struck
down by courts in some states.

A state police agent flew over the neighborhood Dec. 17 in a helicopter and
aimed a thermal imager at the suspect house -- and some neighboring houses
for comparison purposes. They got the reading they wanted, confirming that
the targeted house had an "extreme heat source."

Five days later, based primarily on those results, police asked for a
search warrant. A magistrate granted the request. But when police searched,
they found no marijuana plants. Investigators confiscated -- and are
analyzing -- seeds, some pills and a small amount of plant material and
white powder.

Two months after the initial tip, police have not charged the residents,
which is why they are not identified in this story. Roanoke County Vice
Sgt. Chuck Mason says he will decide whether to charge them after lab
results are returned.

Mason describes the case as routine. He estimates that his investigators
use thermal imaging three to six times a year to corroborate information
and resolve complaints. However, according to Circuit Court files, the
December affidavit in Southeast Roanoke County is the first time Roanoke
County investigators have used the technology to form the "probable cause"
of a marijuana search -- the legal threshold for granting a search warrant.

Criminal defense lawyers, civil libertarians and some who study the
technology contend the equipment is easy to manipulate and infringes on the
Fourth Amendment, the constitutional guarantee against unreasonable search
and seizure.

"The only new information in this warrant is that this house was a little
warmer than the others," said Kent Willis, director of the Virginia chapter
of the American Civil Liberties Union. "The broader question is the issue
of using technology to invade our individual privacy. We know the
government can't wiretap without a warrant first. But we also know the
government can make reasonable public observations."

Where does the use of infra-red technology, or thermal imaging, sit on that
spectrum?

The question has yet to be answered by the U.S. Supreme Court. But several
state appeals courts and federal district courts are split on their decisions.

The Louisiana Court of Appeals and the 11th U.S. Circuit Court of Appeals,
which includes Alabama, Florida and Georgia, have upheld investigators' use
of infra-red technology to obtain a search warrant. But the states of
Montana and California have said that its use violates state and federal
rights. Last month, a Pennsylvania appellate court ruled on a case
involving a heat scan, overturning the conviction of a man charged with
possessing and manufacturing marijuana. The court said the scan violated
the defendant's rights by constituting an illegal and warrantless search.

"Just because you suspect crime, [it] isn't enough" for a search, said
David Baugh, a Richmond criminal defense lawyer who has also worked as an
assistant U.S. attorney.

"It's whether you can check it out in a lawful, nonintrusive manner," he
said. "The police have a responsibility to check it out, yes. But do they
have the right to do it to this degree of intrusiveness?"

Advocates of thermal technology underscore its passive nature since it
merely detects the amount of heat radiating from an object. For more than
30 years, infra-red technology has been used extensively in the military,
particularly during conflict and reconnaissance missions. In the Persian
Gulf War, the technology was used to lock onto targets and assess bomb
damage, according to Brian Yasuda, an electronics engineer at
Wright-Patterson Air Force Base in Dayton, Ohio. The base boasts the U.S.
Air Force's premier research and development lab for infra-red technology.

After the war, the military stepped up its research on nonmilitary uses and
shared its findings with commercial companies. Yasuda works with, among
others, Northrop Grumman Corp. and Texas Instruments. Law enforcement has
become a profitable and viable market for many of these businesses.

The technology is used not only to detect "hot zones" where indoor
marijuana growing operations may be found but also to reveal missing
persons, track suspects at night and view forest fires.

Police in Roanoke and Roanoke County say they have recently used thermal
imaging, most notably during the 1994 investigation of the "Phototron"
marijuana ring, which grew potent, high-quality pot. Nine were convicted on
drug charges in that investigation.

Roanoke Vice Lt. Ron Carlisle said his officers use thermal imaging
sparingly because it is expensive to fly over a region and get a reading.
New hand-held thermal imaging technology may make it more cost-effective,
he said.

"We use the more traditional police investigatory methods to first uncover
pot-growing operations before we resort to expensive technology," Carlisle
said. "It's not like we peek inside your house and see what you're doing.
It's just a heat reading. That's all it is."

And that, say critics, is what investigators should emphasize to
magistrates who are granting searches based on the technology. Heat
readings do not tell investigators conclusively that there is an indoor
marijuana growing operation somewhere, say experts.

The heat emissions of neighboring houses do not reflect anything
significant, according to Carlos Ghigliotty, owner of Infra-red
Technologies in Maryland who has been working in the field for 15 years and
has testified as an expert defense witness on the topic. He contends
investigators use the technology improperly to create the information they
want.

For instance, it is easy to increase the contrast on a photo image to make
the differences look more dramatic, he said. Ghigliotty also says comparing
one house with another is not relevant, since different houses are made
with different materials with varying degrees of insulation.

Investigators' initial research for the Roanoke County search came up
empty. Even after they found that electric bills were not unusually high,
they continued the investigation. But if the power bills are not unusually
high, then how would the home emit an "extreme heat source?"

"It still produces heat," Mason said. "But you're going into an area where
I'm not qualified to render forth opinions."

Virginia State Police, which operated the thermal imager in this case and
has at least one officer trained in the technology, would not comment on
the search warrant or the technology.

The probable cause did not raise any questions for Roanoke County
Magistrate James Stewart, who issued the warrant within five minutes of
hearing the probable cause. Following internal policy, he directed
questions about the affidavit to Chief Magistrate Bobby Casey, who said
thermal imaging is one of many reasons used to support search warrant
requests.

"Until we get a ruling from the court, then we accept any technical, proven
data up to that point," Casey said.

All of this is little comfort to the targets of the search. One of the
residents said he allowed police to rifle through his possessions only
after he saw the search warrant. But now he is not convinced the search was
valid.

"I already feel very violated," he said. "They didn't find what they were
looking for or anything they can charge me with. ...