FBI aircraft are performing flyover imaging runs of an area on Long Island where local authorities have already discovered 10 sets of human remains. The bones and bodies appear to be the work of a serial killer—and perhaps multiple killers—who dumped the bodies in brush near the island's south shore.

The federal agency provided a fixed-wing aircraft for surveillance of the coastal brushlands on April 14, and on April 18 an FBI helicopter joined the search as well. Adrienne Senatore, a spokesperson with the FBI's New York field office, says the flyovers used "high-tech imaging" equipment but would not disclose specifics on technology or tactics. "As far the equipment that is on the aircraft and the helicopter, we're really not discussing that," she says.

Law-enforcement officials often use high-resolution photography as well as infrared thermal imaging from the air to locate missing persons or human remains. "If they were looking for living people, they would be using infrared imaging," says forensic scientist Lawrence Kobilinsky, a professor at the John Jay College of Criminal Justice in New York City. Suffolk County Police Commissioner Richard Dormer said in a news conference last week that Long Island authorities are looking for skeletal remains, for which photography is often more useful.

Human remains do have a detectable thermal signature during decomposition, explains special agent Catherine Sapp of the Georgia Bureau of Investigation, who wrote a 2008 article on aerial photography for the FBI Law Enforcement Bulletin. But that does not last long. "Once you have decomposition to the point that it's just bones, then there's not going to be anything to decompose, so there isn't going to be any heat signature," she says. Skeletal remains, on the other hand, are often highly visible to aerial photography. "Bleached-out bones will jump out at you," Sapp says.

Kobilinsky notes that infrared imagery can also be used to identify areas of disturbed soil, where remains might be hidden. "That might show as a contrast in heat," he says.

So far, the remains located have been recovered by more low-tech means, such as simple manned grid searches. A coalition of some 125 people, including officers from local and state police agencies as well as park rangers, have participated in the search, says Detective Michael Bitsko, a Nassau County Police Department spokesperson. The searchers have been aided by cadaver dogs and by elevated views from the extended arms of fire trucks. "Mounted officers were going in also in and getting elevated looks," Bitsko says.