April 1, 2013

Blind spots in electronic monitoring of sex offenders

California corrections officials find that the Global Positioning System isn't always wired for reliability.

Paige St. John / Los Angeles Times

LOS ANGELES — A little more than a year ago, California began testing the GPS monitoring devices that track the movements of thousands of sex offenders.

click image to enlarge

Parole agent Steve Nakamura uses a flashlight to inspect a GPS locator worn by a sex-offender parolee in Rio Linda, Calif. California had to replace thousands of the devices recently because they proved easy to thwart.

The Associated Press

The results were alarming.

Corrections officials found that the devices used in half the state were so inaccurate and unreliable that the public was "in imminent danger."

Batteries died early, cases cracked, reported locations were off by as much as three miles. Officials also found that tampering alerts failed and offenders were able to disappear by covering the devices with foil, deploying illegal GPS jammers or ducking into cars or buildings.

The state abruptly ordered parole agents to remove every ankle monitor in use from north of Los Angeles to the Oregon border. In their place, they strapped on devices made by a different manufacturer -- a mass migration that left California's criminal tracking system not operational for several hours.

The test results provide a glimpse of the blind spots in electronic monitoring, even as those systems are promoted to law enforcement agencies as a safe alternative to incarceration. The flaws in the equipment raise the question of whether the state can deliver what Jessica's Law promised when voters approved it in 2006: round-the-clock tracking of serious sex offenders.

In a lawsuit over the state's GPS contracting, corrections attorneys persuaded a judge to seal information about the failures, arguing that test results could show criminals how to avoid being tracked and give parole violators grounds to appeal convictions.

The information, they warned, would "erode public trust" in electronic monitoring programs. The devices, they said, deter crime only if offenders believe their locations are being tracked every minute.

"The more reliable the devices are believed to be, the less likely a parolee may be to attempt to defeat the system," GPS program director Denise Milano wrote in a court statement.

State officials say the replacement devices have largely resolved the problems, but officials so far have refused to release test data showing what, if any, improvements were gained.

Through interviews and by comparing censored documents obtained from multiple sources, the Los Angeles Times was able to piece together most of what the state persuaded the courts to black out.

GPS tracking devices are designed to alert authorities if the wearer tampers with the device, tries to flee or strays too close to a school or other forbidden area. Currently, 7,900 high-risk California parolees and felons -- most of them sex offenders or gang members -- wear the devices strapped to their ankles.

WHEN SIGNALS FALL SHORT

The monitors work by picking up signals from GPS satellites and transmitting the location information by cellular networks to a central computer. Just like GPS devices used by drivers or hikers, the monitors can fail where buildings block signals or where cell reception is spotty.

But that is not the monitoring system's sole vulnerability: A Times investigation in February found that thousands of child molesters, rapists and other high-risk parolees were removing or disarming their tracking devices -- often with little risk of serving time for it because California's jails are too full to hold them.

The state's testing was conducted as part of a winner-take-all contest for the nation's largest electronic monitoring contract, worth more than $51 million over six years. Industry experts said they were the most exhaustive field trials they had seen.

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