Executive Summary
- Carrissa Westphal, 34, was arrested on charges of Homicide by Vehicle and DUI.
- The charges stem from a fatal head-on collision on Nov. 7 involving a wrong-way driver.
- Victim Mandy Butler, 43, died from injuries sustained in the crash; a passenger was critically injured.
- Toxicology reports allegedly showed Westphal had a blood alcohol concentration of 0.15%.
CASPER, Wyo. –– The Casper Police Department (CPD) has arrested 34-year-old Carrissa Westphal in connection with a fatal vehicle collision that occurred in November, charging her with homicide by vehicle and driving under the influence. According to a departmental release, the arrest was made on the morning of December 11, 2025, following a comprehensive investigation into the incident on CY Avenue.
The collision took place shortly after 9:00 p.m. on November 7, 2025. Investigators stated that a sedan, allegedly driven by Westphal, was traveling eastbound in the westbound lane of CY Avenue when it collided head-on with an SUV traveling in the correct lane. The driver of the SUV, identified as 43-year-old Mandy Butler of Casper, sustained life-threatening injuries and later died. An unidentified adult male passenger in the SUV survived but required ongoing medical care for life-threatening injuries.
According to the CPD, officers interviewed Westphal during the initial investigation, at which time she acknowledged consuming alcohol prior to the crash. Westphal was transported to Banner Wyoming Medical Center with serious but non-life-threatening injuries following the collision. Police subsequently obtained a search warrant for a blood sample.
On December 2, 2025, the Wyoming Division of Criminal Investigation Laboratory reported that the sample indicated an alcohol concentration of 0.15%. Based on these findings, Casper Police investigators submitted an affidavit of probable cause to the Natrona County District Attorney’s Office on December 8, resulting in the issuance of an arrest warrant.
Detective Jonathan Schlager emphasized the department’s commitment to the case in a prepared statement. "No family should have to shoulder the loss brought on by this crash," Schlager said. "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."
Judicial Proceedings
As this case proceeds through the judicial system, the focus will shift to the evidentiary phase regarding the alleged intoxication and reckless driving charges. Prosecutors will likely rely heavily on the toxicology reports and collision reconstruction data. The Casper Police Department has noted that the investigation remains active. It is important to note that all individuals, including Westphal, are presumed innocent until proven guilty in a court of law.
