The East Tennessee officer shot and killed in Blount County had an active order of protection against the suspect believed to be responsible for his death.
Brian Keith Stalans, 44, of Maryville was arrested and charged with four counts of aggravated assault.
Blount County Sherriff James Berrong said he wished he could "turn back the clock" on an initial visit to an eastern Tennessee home where a police officer was killed later in the day Thursday.
Deputies responded to a domestic call at Stalans' home earlier in the day, but lacked probable cause to take the suspect into custody.
However, investigators told Local 8 news in Knoxville that they believed Stalans set officers up for an ambush because a second call followed that afternoon reporting more violence, and a gun involved.
According to Local 8, the victims in the domestic calls, Stalans' girlfriend and his father, told law enforcement that during the second call, Stalans fired a round into the house 20 to 30 minutes before Moats and a Blount County deputy arrived.
Investigators told Local 8 that Moats was shot during the altercation while trying to take cover behind their car, which was parked about 70 yards away from the home.
Investigators said Stalans opened fire on them from the garage, shooting his .45 caliber pistol five times and hitting Moats in the neck.
The sheriff said the gunman had an active order of protection against him in another county, and had been flagged as a "dangerous individual" in the national crime database.