Five bodies were found March 26 but three children remain missing.
Debris at the accident site and other material found along the riverbanks also was consistent with that vehicle, officials have said.
The Harts moved last spring to Woodland, Washington, telling their real-estate broker "they needed a fresh start" after experiencing prejudice in Minnesota and too much media attention in OR after one child was pictured in a viral photo taken at a 2014 police-brutality protest. The family was in Newport, Ore., about 160 miles southwest of their home, on the morning of March 24, and kept traveling south until they reached Fort Bragg, Calif., in Mendocino County that evening, according to the California Highway Patrol.
"Preliminary results showed Jennifer Hart had a.102 BAC (blood alcohol content)", the Mendocino County Sheriff's Office said in a statement on Friday.
Mendocino County Sheriff Thomas Allman says the body was found Friday morning about 7 miles (11 kilometers) south of where the family's SUV fell into the rain-swollen Eel River last week.
He said examiners also found traces of an over-the-counter antihistamine that can cause drowsiness in the systems of the wife and two children. The crash happened just days after authorities in Washington state opened an investigation following allegations the children were being neglected.
Authorities did not elaborate on items that were found in the river this week, but said that a vehicle seen going into the river on April 6, when a massive storm swamped areas of Northern California. Days later, a tourist spotted the SUV at the bottom of the cliff. Sarah Hart told police that she lost her temper and bent the girl over a bathtub and spanked her.
The Thottapilly family - father Sandeep, 42, mother Soumya, 38, and their two children, son Siddhant, 12, and daughter Saachi, 9 - was driving from Portland, Oregon to San Jose when they disappeared. They later left the state and never registered in local school districts in OR and Washington OR notified authorities they planned to home-school the children.
A few months after the Harts moved next door in 2017, DeKalb said, one of the daughters, Hannah, pounded on his door at 1:30 a.m.