LOS ANGELES (AP) -- Thousands of ankle monitors that track the movements of paroled sex offenders and other criminals were ordered removed and replaced by California officials last year because they were flawed and unreliable, the Los Angeles Times (http://lat.ms/14wUoRM ) reported.
The move was made after field testing of devices made by a division of 3M Co., which had supplied GPS monitors used by about 4,000 parolees. The company was competing for a statewide contract valued at about $51 million over six years.
The company's bid was rejected because of defects found in the devices, the Times said, and they also failed a second round of tests after 3M protested.
The company disputed the allegations.
"This is one agency's testing," said Steve Chapin, vice president of government relations for 3M's electronic monitoring division. "We have the most widely used system in the world. It's been proven time and time and time again to be very safe and reliable."
In February, a Sacramento County judge ruled that Denise Milano, who heads the state's GPS monitoring program, had violated state contract laws but he upheld her decision that the 3M devices failed state standards.
The Times reported in February that more than 3,400 arrest warrants for convicts who tampered with tracking devices had been issued since October 2011.
State corrections officials began field testing the GPS devices in late 2011 and in April 2012 ordered parole agents to remove every 3M ankle monitor in use from north of Los Angeles to the Oregon border and replaced them with devices from another manufacturer.
Parole agents who tested them found problems ranging from inaccurate location reporting to failed tampering alerts and state corrections officials concluded that the public was placed in imminent danger, the Times said.
In some cases, sex offenders might have been able to literally foil the location-tracking by covering the devices with foil, as well as by deploying illegal GPS jammers or ducking into cars or buildings, the Times said, citing court documents and interviews.
The devices were replaced within hours by those produced by another contractor, Houston-based Satellite Tracking of People, and state officials said the replacement devices largely have resolved the problems.
However, state officials said the replacement devices have largely resolved the problems.
Currently, 7,900 people wear the monitors.