Authorities allege a woman was driving while intoxicated during a 2016 rollover crash that killed her boyfriend in northern Wyoming.

Jennifer O'Neil Thomas, 36, is charged with aggravated homicide by vehicle in the death of 34-year-old John Robert Ipes. She could face up to 20 years imprisonment and a $10,000 fine if convicted.

According to an affidavit sworn to by Sheridan County Attorney Matthew F. Redle, a Wyoming Highway Patrol trooper was dispatched early on the morning of June 12, 2016, to a report of a single-vehicle rollover on U.S. Highway 14/16 near milepost 33.

The trooper arrived to find Thomas bleeding, evidently as the result of an accident.

Thomas reportedly told the trooper that she and Ipes had been drinking in Buffalo the evening prior. At roughly 2:30 a.m., they drove to Clearmont to visit a friend, but they arrived in Clearmont to find their friend wasn't home.

The pair slept in the vehicle, Thomas said, until about 5:30 a.m. Shortly before 6 a.m., they started driving back to Buffalo.

About five miles southwest of Clearmont, Thomas said she swerved to miss a deer, lost control of the vehicle and crashed. The vehicle rolled several times, throwing Ipes from the vehicle, according to a crash report from the Wyoming Highway Patrol.

After the crash, Thomas said, she found Ipes laying on the ground. She could not wake him up.

Thomas reportedly told the trooper that she had two and a half drinks in Buffalo before she and Ipes had departed for Clearmont.

The trooper allegedly smelled alcohol on Thomas' breath. A blood sample was taken from Thomas and sent off to be tested by the Wyoming Department of Health Chemical Testing Program.

The results of the test, conducted five days after the crash, showed Thomas to have had a blood-alcohol concentration of 0.17 --  over twice the legal limit to drive -- at the time the blood sample was collected.

An autopsy of Ipes was conducted on the afternoon of June 12. The probable cause of death was listed as "multiple blunt traumatic injuries, secondary to ejection in motor vehicle crash."

Court records show that Thomas made her initial appearance in Sheridan County Circuit Court on Nov. 9. At that hearing, the court ordered her held on $25,000 cash-only bond.

The case was bound over to Sheridan County District Court on Nov. 28 following a preliminary hearing. Thomas was set to be arraigned late last week.