Andrew Blackwood, 24, remained in critical condition Monday night at Carolinas Medical Center in Charlotte, a hospital spokeswoman said.
Blackwood of Rock Hill was thrown from a car during a crash Sunday morning. Stephen Thomas, a friend traveling with Blackwood, died in the wreck.
Police said the two men were traveling at a high rate of speed on Porter Road around 3 a.m. when their car ran off the road and hit a utility pole. Police said neither man was wearing a seat belt and that alcohol was a factor in the crash.
Because both men were ejected from the vehicle, it was unclear who was driving, said Rock Hill Police Lt. Jerry Waldrop. He said a decision on whether to file charges won't be decided until Blackwood's condition is stable and he can speak with investigators.
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A motorcyclist killed in a separate accident Sunday afternoon has been identified as Jason Kenneth Finch, 34, of Charlotte.
Interim Coroner Sabrina Gast said Finch died from injuries that occurred when his motorcycle collided with a truck near Tom Joye Road and Jim McCarter Road in Clover.
The S.C. Highway Patrol has not released more details of the crash.