The driver of a low-cost interstate bus service was charged with four counts of involuntary manslaughter Friday following a brief court appearance on another charge stemming from this week's crash in Virginia that killed four passengers and injured dozens more.

Kin Yiu Cheung, 37, of Flushing, N.Y., had been free on bond, but he was arrested on the new charges shortly after appearing in Caroline County court Friday morning. Cheung was in court to answer to a misdemeanor reckless driving charge stemming from the Tuesday crash on Interstate 95 about 30 miles north of Richmond.

The new charges are felonies, each carrying a sentence of up to 10 years in prison.

"It's never easy to make determinations to bring serious charges, but there was enough evidence to bring the charge," Caroline County Commonwealth Attorney Anthony Spencer said after Cheung's arrest.

Police say Cheung was fatigued when the Sky Express bus he was driving swerved off the highway shortly before 5 a.m., hit an embankment and overturned. It had departed Greensboro, N.C., Monday night bound for New York City with 58 people.

Cheung's lawyer, Murray Janus, called the wreck a "tragic accident," adding he had not had time to talk to Cheung after his latest arrest.