A police officer in Memphis, Tennessee, was shot dead on Saturday night while conducting a routine traffic stop.
According to officials, police received a call from a civilian at around 9:18 p.m. local time on Saturday warning that an officer had been shot.
The man used the officer's radio to report the shooting. Officer Sean Bolton, 33, was transported to a hospital in critical condition with multiple gunshot wounds, but later died from his injuries.
Bolton had been a police officer since 2010. He was also a veteran of the U.S. Marine Corps and served a tour of duty in Iraq.
"Last night we lost not only an officer, but a great man, a dedicated servant to our community, and a family member," Memphis Police Director Toney Armstrong said on Sunday.
At a somber press conference, Armstrong said that Bolton had apparently interrupted a drug deal.
Police identified the suspect as 29-year-old Tremaine Wilbourn. "When you're looking at this individual, you're looking at a coward," Armstrong said.
Memphis Mayor A C Wharton added he had asked the city council to authorize an additional $10,000 reward.
The driver of the car had given police a statement after being taken into custody, Armstrong said. He was released without charges.
Officers also recovered a handgun near the scene of the shooting, The Commercial Appeal reported.
It is the third time in four years an officer had been killed in Memphis.
In 2011, Officer Tim Warren was killed when he responded to a shooting at a downtown Memphis hotel. In December 2012, Officer Martoiya Lang was also killed on duty while serving a warrant.
Armstrong said the latest incident serves as a reminder to "how dangerous" even basic police work can be.
Wharton echoed Armstrong's message, saying Saturday's killing "speaks volumes about the inherent danger of police work."