Prosecutors charged a Casper woman Thursday with aggravated vehicular homicide in connection with an April 23 car crash that killed three people.

The Wyoming Highway Patrol believes Amanda Snay, who was driving a Chevrolet Monte Carlo when it rolled along U.S. Highway 20/26, was under the influence of drugs and alcohol, according to an affidavit filed in Natrona County Circuit Court.

Test results showed Snay had methamphetamine and alcohol in her system, the affidavit states.

Snay was the only person to survive the crash, which occurred 41 miles west of Casper. Adam Tucker, 21, died at the scene. Two other passengers, 31-year-old Adrian T. Produit and 16-year-old Shantel Miller, died later at Wyoming Medical Center. All three had lived in Mills.

In the affidavit, Highway Patrol officer Scott Keane described arriving at the crash at 11:05 p.m. and finding Tucker, Produit and Miller unresponsive. Snay told him that she was the driver and had been drinking.

In an April interview with investigators, which was described in the affidavit, Snay said she and her passengers were returning from Shoshoni. They stopped at the Waltman rest stop at 10:23 p.m. When they resumed the drive, Produit, who was in the front passenger seat, put his foot on the gas, accelerating the car to 75 mph. Produit then took his foot off the gas, but told her to maintain that speed.

Snay, who was 20 at the time of the crash, told investigators that the car's steering and brakes began to experience problems between mile markers 41 and 42. According to her, Produit and Tucker were arguing, so she turned up the stereo. The next thing she remembered was Produit grabbing the wheel.

When asked why Produit did that, Snay told the investigators "to save us," according to the affidavit. She jerked the wheel from him and the car spun out of control. It was traveling at 74 mph at the time.

After leaving the highway, the Monte Carole rolled twice. The three passengers were thrown from the car.

The Wyoming Department of Transportation examined the Monte Carlo and found nothing mechanically wrong with it that would account for the wreck, according to the affidavit.

Snay's blood alcohol level two hours after the crash was .06 percent.

In Wyoming, a person is presumed too drunk to drive if his alcohol level is .08 or greater. However, a blood alcohol level of .05 or greater can be considered with other evidence in determining whether a person was too drunk to drive.

Snay was already being held in Natrona County Detention Center on an unrelated matter when prosecutors charged her in connection with the crash.

She faces three counts of aggravated vehicular homicide and three counts of driving under the influence, causing serious bodily injury. Each vehicular homicide charge carries a prison sentence of up to 20 years.

Reach crime reporter Joshua Wolfson at (307) 266-0582 or at josh.wolfson@trib.com.