Authorities have identified both the gunman who opened fire at a bus station in Virginia on Thursday and the police officer he killed.
Thirty-four year old James Brown of Illinois approached state trooper Chad Dermyer, 37, and shot him several times.
Dermyer and other officers were participating in a training exercise at the Richmond bus station.
Two other women were shot and are expected to recover.
Police have not stated a motive for the shooting but said the gunman had a criminal record.
Dermyer was in uniform and not wearing a protective vest when he was shot.
Najee Wilson, 18, of New Jersey was waiting for a bus when he heard gunshots.
“We heard a lot of people screaming,” Mr Wilson told the Associated Press. “It definitely was a scary experience.”
The Greyhound station in Richmond is just west of the city’s central area.
“It’s just unfortunate these are the days we’re living in, where folks want to harm law enforcement,” said Richmond Police Chief Alfred Durham. “We just want our officers to end their shifts and to go home to their families.”
Dermyer was a former US Marine with two children. Colleagues described him as a “great guy”.
Earlier this year, he and another officer saved a dog running through traffic in Virginia and gained popularity on local television and social media.
“This is a loss that impacts us all,” said Virginia Governor Terry McAuliffe. ” It should inspire prayers for the family, friends and fellow troopers who are mourning tonight, and gratitude for those who protect and serve.”