Sex offenders and violence-prone criminals paroled to halfway houses in Iowa will find it harder to feign their whereabouts to parole officers. Iowa is requiring some offenders to wear an ankle device from iSecureTrac Corp. that captures their movements as recorded by global positioning satellites. Officers, using a Web browser, can access an iSecureTrac database over the Internet and pull up a map showing the path taken by a parolee when away from the halfway house.

Each map is tailored for a specific parolee. A map can show, for instance, areas where a paroled pedophile must remain clear of--such as a school--when going to and from an off-site counseling session. When the parolee returns to the halfway house, he places the device in a docking station, which transmits the data to iSecureTrac. Later this year, Iowa hopes to upgrade the system to provide for real-time transmission of location via a cellular hookup.

Using the same docking station, Iowa authorities can even test parolees on whether they've been drinking. An offender blows into a straw attached to a Mitsubishi Electronic Monitoring System, which will record alcohol levels. The device is attached to the docking station, which transmits the results to authorities.

"Parole agents can't be available 24 hours a day to track offenders," says Lois Osborn, Iowa Department of Corrections electronic monitoring coordinator, "so this system is another tool to help them out with their surveillance."