OMAHA, Neb. -- A brick was dropped from an overpass in Lincoln Thursday night, smashing through the windshield of a passing car. The driver lost control and crashed, but walked away.

Friday, police searched for evidence about who dropped the 40-pound cement block. The Lancaster County Sheriff's Department said the block did not come from the area where it was dropped, off a county road southwest of Lincoln. Whoever dropped the block had to haul it up a hill, according to the Sheriff's Office.

"It shook him up," said Terry Wagner, the Lancaster County Sheriff. "His window was shattered. He couldn't see, that's why he struck the bridge."

Luke Borgman lives in the area where the brick was dropped. He said his brother and his family drove up on the wreck just after it happened.

"They were right behind the car when it happened. They got a little 2-year-old boy. It could have happened to them," said Borgman.

Wagner said he is treating this as a serious crime.

"Anybody who does this has to realize the potential for injury or death is very high," said Wagner. "It's beyond my imagination somebody would think this is fun or just for kicks."

The Lancaster County case is at least the fourth in a series of reports of rocks being dropped from overpasses in the past six months. One rock dropped over the Sprague Street overpass in Omaha killed a Council Bluffs, Iowa, woman.