The victims were pronounced dead at the scene. Potter was treated and released from the hospital for minor injuries.
Melissa Wildeson of 10752 Worleytown Road, Greencastle, testified that she was behind Potter's van on Pa. 16. She said she backed away from him when she noticed that he kept veering off the road.
Wildeson said she saw the van hit the Escort, but did not see brake lights on the van until after the impact.
State Trooper Randy Kane, the investigating officer, testified that Potter's blood alcohol level was .237 percent. Blood samples for the state police lab tests were taken from Potter more than 11/2 hours after the accident, according to testimony.
The accident occurred at 8:09 p.m. April 18 on Pa. 16 West at its intersection with Hill Road, about three miles west of Greencastle.
Hykes, who was traveling westbound on Pa. 16, stopped for eastbound traffic to pass so he could make a left turn onto Hill Road, according to testimony. He was driving a 1991 Ford Escort compact. His son was in the front passenger seat. Both were wearing seat belts, according to a police report.
Potter, driving a 1988 Chevrolet Astro van, was traveling behind Hykes, according to testimony. He failed to stop or go around Hykes on the right, although there was room to do so, according to testimony.
His van slammed into the rear of Hykes' vehicle, pushing it across the center line and into the path of a 1995 Nissan Pathfinder sport utility vehicle driven by Robert Ernest Branco, 48, of Dumfries, Va., according to testimony.
The Pathfinder hit Hykes' car on the passenger side and sent it spinning into a 1972 Chevrolet pickup truck driven by Robert J. Woodward, 42, of Mercersburg, Pa., who was stopped at the stop sign on Hill Road, according to testimony.
Branco suffered minor injuries. Woodward was not injured.
According to Assistant District Attorney Jill McCracken, Potter faces a minimum of six years in prison. He is free on bond pending trial.