RIVERTON — Investigators found a rifle and almost 200 rounds of ammunition in Nicholas Garcia's vehicle after he was fatally shot by law enforcement officers last month in Riverton.

Garcia - who was a felon prohibited from possessing firearms or ammunition - was killed Jan. 10 after firing a 9 millimeter handgun at two agents from the Bureau of Alcohol, Tobacco and Firearms.

Fremont County Attorney Patrick LeBrun released details of the shooting on Wednesday, determining that the shooting was justified. He won't file charges against the lawmen.

Neither officer was injured in the altercation.

Afterward, LeBrun said investigators searched Garcia's truck and found a .308 PTR semi-automatic rifle containing a full 20-round magazine and a round in the chamber, a green tactical vest containing two additional 20-round .308 magazines, and an additional 130 rounds of .308 ammunition.

The 9 millimeter firearm Garcia used when he fired at the officers was located near his body, LeBrun said; one full 9 millimeter magazine was removed from Garcia's pocket, and another 9 millimeter magazine was discovered "in the immediate vicinity."

In Wednesday's press release LeBrun said he will take no criminal action against the officers who killed Garcia, 34, calling the incident a "justified homicide."

In the days prior to the shooting, LeBrun said, a citizen "familiar with" Garcia told law enforcement that Garcia had been receiving ammunition "via common carrier delivery;" Garcia - who also was a registered sex offender - had told the anonymous citizen that he "hated having to register as a sex offender" and "blamed the police for his situation."

"The citizen advised that Garcia was angry at the police and threatened that he would engage in a gun battle if he was ever stopped by the police," LeBrun wrote. "Further investigation was conducted, and as a result, a federal search warrant was obtained for Garcia's residence in Riverton."

Because of Garcia's threats and "the danger involved," LeBrun wrote, law enforcement developed a "specific operational plan" for executing the warrant.

"The plan involved a combination of federal law enforcement and the Riverton Police Department," LeBrun said.

However, before the operational plan was fully implemented Jan. 10, Garcia left his residence, forcing two ATF agents to follow his Ford F250 "by themselves" in their unmarked vehicle, LeBrun wrote.

"Garcia realized he was being followed and attempted to return to his residence," LeBrun said, noting that the agents could see Garcia "repeatedly glancing in his rearview mirror."

At that point, the agents decided to activate their lights and siren and stop Garcia's vehicle at the corner of North First Street East and East Monroe Avenue in Riverton - about one block from his residence, LeBrun said.

He said the decision was made because the agents were concerned that Garcia had weapons and ammunition at his residence, and because of "the advantage" Garcia would have at his home if a confrontation took place there.

When the agents activated their lights and siren, LeBrun said, Garcia "rolled his vehicle to a stop" and "immediately" got out of the truck holding a black 9 millimeter firearm.

"(He) aimed his weapon at the agents and began firing, (moving) towards the agents as he fired," LeBrun wrote.

He characterized the move as an attempt to kill the two federal agents, who "had the right, under Wyoming law, to defend their own lives and each others' lives using deadly force."

The agents retrieved their weapons and returned fire, LeBrun said, and Garcia moved to the front of his truck, "gun still in hand, seeking a better tactical position."

"Garcia was mortally wounded, at this location, by the agents' return fire," LeBrun said, noting that the officers were within their rights to continue using deadly force "until it was clear Garcia's intended course had been stopped."

LeBrun said the entire exchange lasted "less than 15 seconds," and neither agent was hit by Garcia's bullets.

Riverton Police Department officers - who had been notified of the situation when the agents decided to pull Garcia's truck over - arrived at the scene shortly after the gunfire ceased, LeBrun continued.

"Life-saving efforts were under taken with RPD assistance, however those efforts failed," he said.

Representatives from the Division of Criminal Investigation - the agency charged with investigating officer-involved shootings - "happened to be in town," LeBrun continued, so they also were able to arrive at the scene shortly after the incident took place.

"The vehicles were in the same location, (and) all the information was there - it just had to be collected by DCI," LeBrun said, adding that the agency's investigation is now complete.

He said the DCI agents took measurements, collected shell casings, interviewed the officers involved, and interviewed an "eye-witness" who "happened to be driving by" at the time of the shooting.

One of Garcia's bullets came to rest inside a home nearby, LeBrun said, and spent shell casings from Garcia's weapon were recovered at the scene.

On Wednesday, LeBrun said Garcia shot his weapon at least three times, based on the number of shell casings found at the scene.

It's "hard to say" how many times the ATF agents discharged their weapons, LeBrun said, but "it was many."

He was not aware of any stray bullets from the ATF agents impacting private property.