MINNEAPOLIS (WCCO) — Investigators say an Elk River man admitted Monday to throwing screws onto streets in central Minnesota.

WCCO reported last week about nails and screws damaging cars in Sherburne County.

Someone spotted the 63-year-old suspect after deputies posted a picture of his SUV on Facebook. Deputies tracked him down, and say he had a five-pound box of screws inside his car. Investigators are trying to figure out why he did it.

In Big Lake alone, police had about 150 reports of damaged cars.