CNN  — 

The sheriff’s office in Calaveras County, California, thinks that a body found Thursday in a river is that of a freelance automotive writer who disappeared while taking a motorcycle on a road test.

David Gordon Johnson, 44, was reported missing June 5 and the motorcycle he was to write about was discovered two days later at a river access point.

The sheriff’s office said Friday its investigation led detectives to believe that Johnson had drowned accidentally.

David Gordon Johnson with his fiancee, Jacklyn Trop.

The body found Thursday was in the Mokelumne River near the inlet of Lake Pardee. The medical examiner’s office is looking into cause of death.

Johnson’s fiancée, Jaclyn Trop, told CNN affiliate KCRA earlier this month that he was last heard from when he texted a friend to say he was sitting near a creek before heading home on the Honda CB1000R he was riding for Motorcyclist magazine.

Calaveras County is 90 minutes southeast of Sacramento.

Personal items found with bike

California Highway Patrol officers found Johnson’s motorcyle parked at a rest stop near the town of Mokelumne Hill in Calaveras County. The bike, discovered just after midnight Saturday, was found with Johnson’s helmet and gloves, KCRA reported. His phone, laptop and backpack were found close to the nearby Mokelumne River, the news station reported.

Trop said she and Johnson had spent the weekend together in Los Angeles before he returned to Northern California, making stops in Las Vegas and Mammoth.

They were out of touch for 12 hours Tuesday and into Wednesday, Trop told KCRA, but he messaged her at 2 a.m. to apologize for not reaching out, saying his cellphone had died and he was navigating tricky and icy roads after the sun went down.

“I had a great time before it got dark,” Johnson texted, according to the affiliate. “That part of the Sierra is just stupidly spectacular. Anyway, I’m so sorry I worried you. Yes, I am okay and alive, but I am WIPED.”

David Gordon Johnson's body was found in the Mokulmne River in Calaveras County, California.

“I just really hope he’s alive, because thinking about the alternative yesterday was … I don’t even have words for it,” Trop told KCRA. “I was completely gutted, and I would still feel that way if they hadn’t found the bike.”

Search efforts have been expanded, with California Highway Patrol H20, Calaveras County Marine Safety Division and several other search and rescue groups canvassing the area in an effort to find Johnson.

CNN’s Jenn Selva contributed to this report.