He was set on making the trip from Arizona to Michigan.

Police said the Detroit-area man, identified in news reports as Ray Tomlinson, and his 92-year-old mother spend winters in Arizona and were heading home this week.

Tomlinson, 62, had picked up his alleged 31-year-old girlfriend from a Phoenix-area mental health facility Sunday. She was riding shotgun. His mother was sitting in a wheelchair in the back of his van. And the trio had 1,900 miles ahead of them.

But somewhere along the way, the journey took a bizarre turn.

They had reportedly reached New Mexico on Monday when Tomlinson nudged his girlfriend. “I just said, you know, you want something?” he told WDIV. “At this point in time she was stiff. There wasn’t jerking or moans or groans, or cries for help, she just fell asleep.”

She had substance abuse problems and may have taken oxycodone during a pit stop in Flagstaff, Ariz., said Jere Green, the police commissioner in Warren, Mich., where Tomlinson was headed.

This is where it gets a bit strange.

Tomlinson didn’t stop or call for help. He checked the Internet on his phone to find out what to do with a corpse and learned he apparently had 48 hours to get it to a morgue.

“I just drove and drove, and I knew I’d be in some kind of trouble,” he told WDIV.

Tomlinson said he was planning to wait and take her body to the Macomb County Morgue when he reached Michigan. His reasoning? His mother was in the van and he didn’t want police to impound it — or arrest them — while they investigated, news reports said.

“There is no crime. It’s not illegal for carrying a body across the country,” he later said.

Then someone at the care facility called the woman’s cellphone to check on her. “It’s a courtesy call,” Green told the Associated Press. “He answers and said, ‘She can’t talk. … She’s dead.'”

The caller told him to immediately phone police. When he refused, the facility did, WDIV reported. Michigan police contacted Tomlinson, who met them Tuesday.

When officers got to his son’s home in Warren, north of Detroit, Tomlinson was sitting on the curb, crying, the AP reported. His mother was in her wheelchair in the van. And the body was in the front passenger seat — still wearing a seatbelt and sunglasses.

“She obviously had been dead for at least 24 hours in screeching heat,” Green told the AP.

A neighbor told WJBK: “If you’ve ever smelled a dead body before — you never get that out of your head. … As soon as the police opened the door, thank God there was a good breeze going because you would just get a whiff of it once and a while.”

The Macomb County Medical Examiner’s office has the body and police said the postmortem exam showed no sign of foul play, but they were awaiting a toxicology report Wednesday. Tomlinson’s mother was taken into protective custody, WDIV reported.

Tomlinson has not been charged with a crime, according to news reports. WDIV said the charge police were considering is failure to produce a body, which is a misdemeanor.

Tomlinson could not be reached Wednesday night and Warren police declined comment. He reportedly gave police the explanation for his actions, “which made sense to him,” Green told the AP. But “was he committing a crime or was it stupidity?”