More than a year after an SUV with a woman and her three kids inside plunged 50 feet off of a cliff into Lucky Peak Lake in Idaho, authorities have determined that the fatal wreck was intentional.

The Ada County Coroner's Office has ruled the deaths a triple homicide-suicide.

On June 2, 2016, 40-year-old Noel Bankhead drove her Land Rover off of a cliff, killing herself, her daughters Anika Voermans, 13, Gwyneth Voermans, 8, and her son Logan Voermans, 11.

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The impact of the crash, as a chilling photo shows, crushed the roof of the vehicle. Witness accounts and an analysis of the road led authorities to their conclusion.

Authorities said that witnesses told investigators that Bankhead was driving on a state highway when she turned off and positioned the car toward the cliff, then suddenly accelerated.

Officials said they found nothing mechanically wrong with the vehicle.

The Ada County Sheriff's Office cited witness statements and lack of skid marks in making its determination that Bankhead acted deliberately. Toxicology tests found no medication or alcohol in Bankhead's system.

"Witnesses later told investigators Noel Bankhead was driving her Land Rover northbound on Idaho 21, slowed down, turned on to Spring Shores Road, and positioned the car towards the cliff and suddenly accelerated," a Friday press release said, according to the Idaho Statesman.

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The official cause of the deaths was drowning associated with blunt force trauma.

Bankhead and her husband divorced three years ago.

The Associated Press contributed to this report.