Investigators made an unexpected discovery during the autopsy of the Modesto man killed Tuesday in a Tuolumne County car crash.

They had believed Roy Leross Nordfelt was driving at the time of the crash on Highway 108 near the Tuolumne-Stanislaus county line. But bruising from his seat belt indicated he was actually in the front passenger seat.

With this information, and a sign language statement from an injured passenger unable to speak, authorities now suspect a man who claimed to be a passenger was actually driving, said Officer Tom Wills of the California Highway Patrol.

Authorities say they have also uncovered information that 23-year-old Jeremy Orr was using drugs in the hours leading up to the crash.

Orr has been jailed and CHP investigators will likely ask the District Attorney's Office to charge him with vehicular manslaughter and driving under the influence, Wills said.

Orr told investigators he was riding in Nordfelt's Mitsubishi Eclipse convertible when it flipped on Highway 108 about 3:30 a.m. Tuesday. He also said Nordfelt, 49, had been up all night using methamphetamine and was driving when the accident occurred, Wills said.

"We were basing everything on what our passenger (Orr) told us," Wills said.

That information led CHP officers to report Nordfelt was intoxicated. Now, they won't know the truth until a toxicology test is completed. Wills, however, said there is no indication he was.

Officers were initially leery of Orr's story because the Modesto man said he and passenger Shelly Tyson, who was seriously injured in the accident, were in the back seat, leaving Nordfelt alone in the front.

"There was just something that gave us the sense that something wasn't right," Wills said.

At Tuesday's autopsy, suspicions were confirmed.

Wednesday, CHP Officer Ken Austin visited Tyson at Doctors Medical Center of Modesto, where she is being treated, to try and piece together what happened.