Shipping tycoon Angela Chao was drunk when she inadvertently reversed her Tesla into a pond and drowned last month at a Texas ranch, police say.
Blanco County Sheriff’s Office found her blood alcohol level was nearly three times the state’s legal limit.
The 50-year-old died after dinner on 10 February with a group of friends at the estate near Johnson City.
Her brother-in-law, Senate Republican leader Mitch McConnell, cited the tragedy in his resignation speech.
On Wednesday, Blanco County Sheriff’s Office released the findings of its investigation concluding Ms Chao’s death was an “unfortunate accident”.
It is illegal to operate a motor vehicle under the influnce anywhere in the state of Texas.