KSP said Trooper Hayden Phillips, 30, stopped a vehicle on I-65 around 2 p.m. Central time. Warren County sits about two hours southwest of Louisville. Phillips was shot during the stop and later died from his injuries.
State police issued a Blue Alert, a warning system used for a "severe attack on law enforcement." Louisville Metro Police took a suspect into custody around 6:30 p.m., and KSP canceled the alert once he was in custody. Police identified the man charged with murder as Emonnie Branch, 51.
The shooting highlights the risks officers face during traffic stops, a routine duty that turned deadly for Phillips.
The stop turned fatal in under five hours, from the shooting to Branch's arrest two hours away in Louisville.