Casper Woman Arrested In Deadly Wrong-way Crash On CY Avenue

Casper Police Arrest Suspect in Fatal Wrong-Way Crash on CY Avenue

Casper police have arrested a 34-year-old woman following a month-long investigation into the fatal wrong-way crash that occurred on CY Avenue on November 7, 2025.

Officers took Carrissa Westphal, of Casper, into custody on the morning of December 11 on recommended charges of Homicide by Vehicle, Driving Under the Influence, and Reckless Endangering. The arrest follows an affidavit of probable cause submitted by investigators on December 8 and a subsequent arrest warrant issued by the Natrona County District Attorney’s Office.

According to investigators, the crash happened shortly after 9 p.m. when a sedan traveling eastbound in the westbound lane of CY Avenue struck an oncoming SUV head-on. Westphal, identified as the driver of the sedan, was hospitalized with serious but non–life-threatening injuries.

The SUV’s occupants suffered critical injuries. The driver, 43-year-old Mandy Butler of Casper, later died at the hospital, according to the Natrona County Coroner. The passenger, an adult male, survived and continues to receive medical care.

During the initial investigation, officers interviewed Westphal, who acknowledged consuming alcohol that evening. Police later obtained a search warrant for a blood test. On December 2, the Wyoming Division of Criminal Investigation Laboratory reported Westphal’s blood alcohol concentration as 0.15%, nearly twice the legal limit.

"No family should have to shoulder the loss brought on by this crash” Detective Jonathan Schlager said in a statement announcing the arrest. “Our investigators have taken every step to ensure the facts are clearly established, and we will continue supporting the pursuit of accountability through the justice process. The effects of this incident will be felt in this community for a long time.”

Police say the case remains active as it moves through the court system.

The November 7 crash was the subject of an earlier public briefing, in which the Casper Police Department confirmed that alcohol was being investigated as a contributing factor. Officers at the scene were still processing the collision around 2 a.m. on November 8 when a separate incident occurred: a Natrona County Sheriff’s Office pursuit involving a suspected impaired juvenile driver was terminated near Wyoming Boulevard and CY Avenue. Moments later, the fleeing vehicle crashed into an unoccupied Casper Police vehicle near the initial crash site. The juvenile driver was seriously injured. No officers or bystanders were hurt. Due to the involvement of multiple agencies, the Wyoming Highway Patrol is handling the investigation into that secondary crash.

In its statement, the Casper Police Department reaffirmed its commitment to public safety and professional policing as the community continues to grapple with the impact of the November 7 tragedy.