JEFFERSON COUNTY, MO (KTVI-FOX2now.com) - Authorities in Jefferson County are searching for whoever is stealing ATV's worth thousands of dollars. Five have been stolen in the last month and now investigators are warning people to make sure their ATV's are secure. Sanderson's Polaris ATV was stolen right out of the backyard of his home near Arnold. The crime happened last week when Mike wasn't home.

"First I'm mad because I've been violated," said Mike Sanderson.

Mike tells us he kept his ATV in his backyard. He believes the thieves just pushed it out through his back gate. Besides Sanderson's, two ATV's were stolen in the DeSoto area, and two others were stolen near Festus- all just in the last month.

"We go through phases in terms of ATV thefts," said Lieutenant Dave Marshak with the Jefferson County Sheriff's Department.

Marshak says there are active investigations into all of the thefts. But so far none of the ATV's has been found. Marshak tells us the four wheelers can be attractive for criminals.

He said, "They can be put on the back of a vehicle or be ridden away if the keys are in there. Also the parts generally speaking represent a pretty fair market value if you sell them on the street." Marshak says to some degree people have to take security into their own hands.

In two of these cases, the keys were left in the ATV's. Sanderson's keys were not in his ATV. He thinks the thefts are a sad sign of the times.

"People are just desperate for anything. You know, they're going to do anything they can to make a dollar and whether they violate somebody else's rights they don't care," explained Sanderson.

At this point, police have no suspects in the thefts. If you have any information, call the Jefferson County Sheriff's Department.