A crash in which a sport utility vehicle carrying a family plummeted off a California cliff overlooking the Pacific Ocean last week may have been intentional, the authorities said on Monday.

The vehicle, carrying Jennifer and Sarah Hart and at least three of their six adopted children, had stopped on a dirt pullout off Highway 1 on March 26 before accelerating about 70 feet to the edge of the cliff, the California Highway Patrol said, citing an analysis of the vehicle’s onboard computer. Investigators also did not find skid marks at the scene that might have indicated a collision.

“It was pure acceleration from the last brake application until it hit the bottom of the cliff,” Greg Baarts, the acting assistant chief of the California Highway Patrol’s northern division, told reporters on Sunday night.

Preliminary evidence indicated that when investigators reached the S.U.V., its speedometer showed a reading of 90 miles per hour, Mr. Baarts said.