The GPS monitoring system – which holds more than two million records – went offline on Tuesday leaving authorities in 49 states blind to offender’s movements for around 12 hours.
BI Incorporated, which runs the system, said the problem was caused by a data overload.
As a result, prisons and correction agencies were prevented for receiving notifications on tens of thousands of people nationwide.
In Wisconsin prison officials made local police and probation agents detain around 140 offenders at local jails until the system was back up.
Those temporarily imprisoned had not previously been aware they were being tracked, Wisconsin Department of Corrections spokeswoman Linda Eggert confirmed.
Correction Secretary Rick Raemisch declared in a statement: ‘Due to a system failure beyond our control, we faced a challenging and unprecedented event for our Electronic Monitoring Center.’
He added though ‘the situation was managed safely and efficiently with the number one priority being public safety’.
BI spokesman Jock Waldo said the company had significantly increased its data storage capacity but ‘in retrospect… should have been able to catch this’.
Mr Waldo said tracking devices had continued to record the movement of offenders, parolees and other convicts, but the information was not immediately available to local authorities.
He added those being tracked, and not brought in as a precaution on Tuesday, were unaware of any problems with the system.
Along with GPS systems, the outage affected in-home radio monitoring – commonly used to check curfew compliance and breathalyser tests – Mr Waldo told the AP news agency.
BI workers were unaware how quickly the offender database was filling up before exceeding its limit on Tuesday, he added.
‘People in our development group knew there was a threshold,’ the spokesman said. ‘They’ve never in their careers… seen a system hit such a database threshold. It speaks of the enormity of the data we collect.’
BI has contracts with around 900 government agencies across the country for monitoring and notification services.
- An earlier version of this story incorrectly included a photograph of electronic tagging equipment which, it has been pointed out to us, was not involved in the system failure.