Updated

A cellphone possibly belonging to a member of the Hart family, all eight of whom are presumed to have died when their SUV mysteriously plunged off a California cliff, was discovered Wednesday near the crash site, authorities said.

Searchers looking for the missing Hart siblings found the phone and authorities believe that it could belong to one of the family members, the Mendocino County Sheriff’s Office told KOIN-TV.

There have been no signs of the three children who remain missing but presumed dead in the crash that killed Sarah and Jennifer Hart and three of their adopted children. Mendocino County Sheriff Tom Allman said one person reported something bobbing in the water nearly 40 miles out at sea, but divers didn’t find anything, according to Oregon Live.

hart family

The Hart family's vehicle was found at the bottom of a cliff on March 26. Three of the children are still missing, but presumed dead. (AP)

Five bodies were found March 26 near Mendocino days after Washington state authorities launched a probe into the Harts for possible child neglect.

The bodies of three children — Markis, 19; Jeremiah, 14; Abigail, 14 — were found at the scene. The search for the three other children — Devonte, 15, Hannah, 16, and Sierra, 12 – was still ongoing as police looked for additional clues to help determined what may have led to the crash.

Allman said there is “every indication” all six Hart children were in the vehicle at the time.

Police said Thursday that Jennifer and Sarah Hart were not wearing their seat belts when the vehicle plunged into the waters off the Pacific Coast Highway, about 150 miles north of San Francisco.

“I’m leaning to say that this is more of a crime than it is a crash,” Allman told FOX12 Oregon.

California Highway Patrol said in a Wednesday news release the family of eight was believed to be in the Newport, Ore. area around 8:15 a.m. on March 24, two days before their vehicle was found. A map released by California Highway Patrol showed the coastal route the family possibly took based on cellphone pings, Officer Cal Robertson told Oregon Live.

Police are hoping a surveillance video taken just after 8 a.m. Sunday, appearing to show Jennifer Hart at a Safeway in Fort Bragg, could lead to more information on where the "Hart Tribe" was located Sunday night — when their trail went cold.

I’m leaning to say that this is more of a crime than it is a crash."

— Mendocino County Sheriff Tom Allman

The search for what caused the deadly crash has led investigators to examine “red flags” in the Harts’ past. On Tuesday, Alexandra Argyropoulos, a former friend of the family, told The Associated Press she alerted Oregon welfare officials about Jennifer and Sarah Hart because she felt they were withholding meals from their six adopted children.

A similar instance also prompted neighbors Bruce and Dana DeKalb to alert Child Protective Services three days before the family was found dead. They feared Devonte — who gained nationwide fame after a photo of him at a 2014 Portland, Ore., rally holding a “Free Hugs” sign went viral — was going hungry because he'd been coming over to their Woodland, Wash., house too often in the past week asking for food.

Fox News’ Katherine Lam and the Associated Press contributed to this report.