(CNN) -- The driver of a paratransit van rammed a motorcyclist, killing him, California authorities said Saturday.
Police said the van dragged the wreckage of the bike for a mile down eastbound Interstate 580 before the driver stopped.
The motorcycle driver was "hit and pulled under the bus and came out. The van kept pushing the bike down the road," said San Leandro police Lt. Greg Lemmon.
The biker, who was not identified, died at the scene.
Witnesses told police the victim was part of a group of six to eight motorcyclists riding together, some of whom were wearing jackets with the Hell's Angels logo.
Witnesses said the van tried to change lanes when it hit the motorcycle Saturday afternoon, Lemmon said.
"Based of the initial accounts of the witnesses, they are saying it did not appear to be an accident," he added.
The van was not carrying any passengers at the time. The driver was arrested, but police were still trying to identify him late Saturday night by comparing fingerprint records, said San Leandro police Sgt. Doug Calcagno.