Defendant in highway rock-throwing that maimed Ohio teacher starts jail before sentence is set

FILE- In this Oct. 21, 2014 file photo, Sharon Budd speaks with her husband Randy after being discharged from Geisinger Health South Rehabilitation Hospital in Danville, Pa. Budd was struck by a rock dropped from a bridge overpass onto her vehicle in July of 2014. Brett Lahr, one of four defendants in the highway rock-throwing incident that left Budd severely injured, is in jail Monday, April 6, 2015, after he opted to start serving time before his sentence has been determined. (AP Photo/Ralph Wilson, File) (The Associated Press)

FILE - This Oct. 22, 2014 file photo, Randy Budd, left, helps his wife Sharon Budd out of their car after returning home in Uniontown, Ohio. Sharon Budd was struck by a rock dropped from a bridge overpass onto her vehicle in July of 2014. Brett Lahr, one of four defendants in the highway rock-throwing incident that left Budd severely injured, is in jail Monday, April 6, 2015, after he opted to start serving time before his sentence has been determined. (AP Photo/The Repository, Scott Heckel, File) Mandatory Credit (The Associated Press)

HARRISBURG, Pa. – One of four defendants in a highway rock-throwing incident that left an Ohio teacher severely injured is in jail after he opted to start his sentence before it's imposed.

A jail official said Monday that 19-year-old Brett Lahr spent the weekend behind bars in central Pennsylvania even though the judge hasn't yet accepted his plea of no contest to conspiracy to commit aggravated assault.

Lahr and three other teens were arrested last July after a nearly 5-pound rock was dropped from an overpass and crashed through the windshield of a car on Interstate 80, about 60 miles north of Harrisburg.

The rock landed on the head of Uniontown, Ohio, teacher Sharon Budd, who remains under 24-hour care and still needs additional surgery.

Lahr's lawyer wouldn't say why he entered jail early.