Beware motorists: thieves in some states have been targeting cars parked in carpool lots. According to a story from an NBC affiliate in Grand Rapids, Michigan, cars parked in park and ride lots have been targeted by thieves.

WOOD TV says Michigan State Police said they are investigating seven different cases in which catalytic converters have been taken off cars in the lots and that the local Sheriff's department is also looking into the situation.

"It seems to be kind of a hot item right now, to be going to the local car pool lots and removing these from vehicles," Michigan State Police Trooper Ian Fields said.

Fields told WOOD TV that troopers will be increasing patrols throughout the day. He also recommends drivers who use the lots to park as close to the front of the lot as possible, making the car more visible from the road. The thieves may prefer the isolation at the back of the lots.

Thieves are after catalytic converters because of precious metals like platinum that are inside. Converters can be turned into scrap metal yards where thieves collect anywhere between $20 and $160.

Mechanics said replacing catalytic converters can cost drivers anywhere between $400 and $3,000, depending on how much damage the thieves do the car and what kind of car the converter is taken from.