ST. CHARLES, Mo. (AP) – A new tracking system in St. Charles County is helping police find people with Alzheimer’s disease or autism who may wander by themselves.

The St. Louis Post-Dispatch reports that about 20 people with such conditions in St. Charles County are using Care Track, a monitoring device that’s worn like a wrist watch.

The device began as a way to track endangered animals. Police can find its location from one mile on the ground, five miles from the air or 12 feet under water.

Police Cpl. Steve Case, whose son has autism, started the program by teaming up with the St. Charles County Health Department.

More than 500 agencies around the U.S. use the device, but the company says this program is believed to be the only one in the St. Louis-area.