The body appears to be that of an African American female, but the age and a positive identity could not be determined according to the Mendocino County Sheriff's Office.
Officials are investigating the possibility that the body may be one of the two missing Hart girls but identification will most likely be done through DNA analysis, a process that can take several weeks.
The California Highway Patrol says that crash involving an SUV plunging off a cliff, killing a family may have been an intentional act.
Capt. Greg Baarts with the CHP Northern Division says information pulled from the SUV's software shows the vehicle was stopped at the highway pullout before it accelerated straight off the cliff.
Baarts says the electronic information combined with the lack of skid marks led officials to believe it was intentional.
A Mendocino County Sheriff's Office spokesman says authorities believe at least one felony was committed but declined to specify.
The California Highway Patrol identified the adult victims as Jennifer Hart and Sarah Hart, both 39. The agency says their SUV was driving Monday on the Pacific Coast Highway when it pulled into a dirt turnout and continued driving off the cliff.
Jennifer and Sarah were a married couple who had previously resided in West Linn, Oregon. It was later learned they had six adopted children. Three children were confirmed to have died in the crash.
The Sheriff's Office, the California Highway Patrol, and the United States Coast Guard out of Fort Bragg initiated a second search after learning that three other children were missing following the crash.
Fifteen-year-old Devonte Hart drew wide media attention after being photographed hugging a Portland, Oregon, officer during a demonstration over the unrest in Ferguson, Missouri.
Child welfare officials in Washington state had recently visited the home of two women who died along with three children in that crash according to officials.
Clark County sheriff's Sgt. Brent Waddell told The Associated Press that the family lived in Woodland, Washington, and recently had a visit from Child Protective Services.
He says the sheriff's office later entered the house and found no obvious signs of trouble or violence.
The Associated Press contributed to this report.