On the evening of March 12, 2023, the small community of Hermann, Missouri, was shaken by a violent confrontation at a local business. Detective Sergeant Mason Griffith, a 34-year-old White male and twelve-year veteran of the Hermann Police Department, responded to a disturbance call at Casey’s General Store on Highway 19 alongside Officer Adam Sullentrup. The officers arrived at the convenience store around 9:30 p.m. to investigate a report of an irate individual.
Upon entering the establishment, they encountered a man who initially provided them with false identities, referring to himself as 'Justin' and 'Kevin.'
As the interaction progressed, the officers discovered that the individual was actually Kenneth Lee Simpson, a 35-year-old man with a history of criminal activity and multiple outstanding felony warrants from Warren and Franklin counties. When Griffith and Sullentrup attempted to take Simpson into custody, the situation escalated rapidly. Simpson produced a handgun and opened fire on the officers before they could effectively subdue him. Sergeant Griffith suffered fatal gunshot wounds during the exchange, while Officer Sullentrup was struck in the head, sustaining critical injuries that would require months of hospitalization and rehabilitation. Griffith was transported to Hermann Area District Hospital, where he succumbed to his injuries, leaving behind a wife and two children.
Following the shooting, Simpson fled the convenience store on foot and barricaded himself inside a residence on Market Street, located just across the highway from the scene of the crime. Law enforcement agencies from across the region, including the Missouri State Highway Patrol and SWAT teams, descended on the town, establishing a perimeter around the house. A standoff ensued for approximately 14 hours as negotiators attempted to resolve the situation. During the siege, authorities utilized flash-bang devices in an effort to force a surrender. Finally, on the afternoon of March 13, Simpson emerged from the residence and was taken into custody without further violence.
Kenneth Lee Simpson was subsequently charged with first-degree murder, first-degree assault on a special victim, two counts of armed criminal action, and unlawful possession of a firearm. Prosecutors announced their intention to seek the death penalty given the severity of the crimes. Due to the high profile of the case in Gasconade County, a change of venue was granted, moving the proceedings to Franklin County, with a jury pool selected from Greene County to ensure impartiality. As of early January 2026, jury selection had commenced for Simpson’s capital murder trial, with court proceedings scheduled to fully begin later that month.
