FARGO (AP) - A man convicted of raping four Fargo women in 1992 will be monitored with Global Positioning System equipment when he is released from prison in July, authorities say.

Gero Mahto, 37, will be one of 19 convicted sex offenders statewide who are being tracked by GPS equipment.

Officials say GPS tracking does not necessarily prevent a crime, but it lets authorities know where someone is.

"I think the community will just feel more safe knowing that an officer is going to be able to get on the computer and see (Mahto's) location," said Barb Breiland, the manager of the North Dakota Parole and Probation's sex offender program.

Mahto is expected to head to Jamestown after his July 5 release. He has completed a chemical addiction treatment program, state prison Warden Tim Schuetzle said.

East Central District Judge Steven McCullough ordered Mahto back to prison for 55 weeks last September and ordered him to complete the treatment program.

Mahto originally was sentenced to two 10-year prison terms and 10 years of probation, but his stay was shortened with credit for good time and parole on the first sentence. He was released in August before being sent back to complete treatment. A civil commitment attempt failed last year.

When Mahto is released, he likely will be placed on the state's most active GPS tracking system, said Terry Grumbo, the state's GPS program coordinator.

North Dakota's program has three levels of GPS tracking that range from passive to active.

The active system sets up exclusion zones around places such as schools or victims' homes. Authorities are alerted if an offender enters those zones, Grumbo said.

The passive system records locations each minute, and downloads that information once a night. All 18 offenders monitored by GPS in North Dakota are on the medium-level system, which does not include exclusion zones, but involves real-time response, Grumbo said.

Grumbo said exclusion zones can be difficult because the excluded perimeter is circular, which can make it difficult to avoid the area at times.

The GPS units involve an ankle bracelet and a large cellular phone. The phone, which does not make outgoing calls, picks up a signal from the ankle bracelet and will immediately detect if it has been tampered with, Grumbo said.

Cell phone service sometimes has problems, and that can make tracking difficult in rural areas, Grumbo said.

The cost for each unit ranges from $4.75 to about $10 a day, depending on how active the system is Breiland said.

Sex offender task forces in North Dakota determine whether someone should be put on GPS monitoring and how active the system should be, based on such factors such as the offender's risk level and cooperation, Breiland said.

The makeup of each task force differs, but usually includes law enforcement officers, federal and state probation officers, state's attorneys and sometimes victims' advocates and treatment personnel.

Task forces are in Fargo, Grand Forks, Minot, Bismarck and Jamestown. There are plans to establish them in Dickinson, Devils Lake and Williston this year, Breiland said.