A Loudoun County man and his 8-year-old son died late Thursday while returning home from a Baltimore Orioles game when the pickup truck in which they were riding rolled over on Interstate 70 in Frederick.

Chris Coffelt, 44, and his son Matthew, of Round Hill, were traveling west on the highway when the 2002 Ford F250 veered from the road and hit a guardrail near South Street, said Maryland State Police Trooper Steven Boswell.

The truck's driver, James Loveless Jr., 38, and his son James Loveless III, 8, also of Round Hill, were injured in the accident. The elder Loveless was released yesterday morning from the Maryland Shock Trauma Center, a hospital spokeswoman said. His son remained in serious condition yesterday afternoon at Johns Hopkins Hospital.

No charges have been filed in the accident, and the investigation continues, said Frederick County State's Attorney Scott L. Rolle.

Chris Coffelt, a lifelong Loudoun County resident, was assistant superintendent of Purcellville's water department. He had worked for the town for 15 years and was known as a practical joker and jovial spirit, said Town Manager Robert Lohr.

"He was the type of employee that everybody loved," Lohr said. "He was always good for a laugh or to tell you something funny."

Coffelt was born in Leesburg and graduated from Loudoun County High School in 1979, said Lowell Coffelt, Chris Coffelt's father.

Coffelt and Loveless had been friends for years, Lowell Coffelt said. Loveless bought Chris Coffelt's home last year, and Coffelt was building a new home in the same area.

Lowell Coffelt said his son was an avid hunter and liked to spend as much time as possible with his family -- his wife of 24 years, Debbie, son, Matthew, and daughter, Mandy, 11.

"He was a good family man," said Coffelt, 70.

Matthew Coffelt and James Loveless III, known as J.W., played on the same Little League team, the Red Sox, and had just finished second grade at Mountain View Elementary School in Purcellville.

The four had watched the Orioles beat the Boston Red Sox on Thursday night. They were about 25 minutes from home when the truck left the road, at 11:02 p.m.

It was unclear what caused the accident, authorities said. No other vehicles were involved.

Staff writer Rosalind S. Helderman and researcher Bobbye Pratt contributed to this report.