High-tech keeps eye on parolees

SCRANTON, Pa. -- The green dot on the city map that fills Christine Tocki's computer screen doesn't move for several minutes, and that is exactly what she wants to see.

The dot represents a sex offender sentenced to home confinement. Its position tells Tocki, an assistant Lackawanna County district attorney, that the man is inside his house.

At any time of day, Tocki can find out where the offender is, thanks to the Global Positioning System, a network of 24 satellites orbiting 12,000 miles above the Earth.

Originally developed for the military, GPS is used for land surveying and as portable units for hikers, and is available as an option in cars to help motorists navigate unfamiliar areas.

Now it also is being used in at least 20 states to keep constant track of more than 1,000 offenders, many of whom have committed crimes involving sex or domestic violence.

"It's one less thing for victims to worry about. They can move around more freely without fear of crossing paths with their attackers," Tocki said.

In ordinary electronic monitoring systems, offenders wear ankle bracelet transmitters that broadcast a signal to a receiver or tracking device in their home; if the offender strays too far, the receiver sends a message to authorities. For offenders allowed to leave home at certain times, such as going to work, authorities have to assume they're behaving themselves when they're out of range of the receiver.

"The shortfall of electronic monitoring is that you know only if the offender is home. You don't know what happens when he leaves the home," said Steve Chapin, chief executive officer of ProTech Monitoring Inc., which markets one of the global positioning systems.

Widely used device

The GPS system also uses an ankle bracelet, but the receiver is a portable device that the offender carries with him anywhere. In addition to signals from the bracelet, the receiver gets location information from the GPS satellites and communicates with authorities via a cellular phone connection.

The portable GPS receiver is cumbersome, slightly smaller than a child's lunch box and weighing 3.8 pounds. It's also more expensive; ProTech rents the units for $10 to $12 a day, compared to $3 to $6 for traditional electronic monitoring. The GPS units are being used most widely in Florida, which has nearly 580 offenders on the system.

"We've found instances where one or two of them would rather go back to prison or jail, because they feel it's too confining," said Joe Papy, director of a Florida corrections department in Tampa where about 70 offenders are on GPS.

The system's use of cellular connections means it is prone to the same problems that frustrate cell phone users, law enforcement officials say. The signal can fade when an offender enters a metal building or passes obstructions.