The man police say shot and killed a Fargo police officer and shot two more officers and another person used a "binary trigger" device that allowed him to fire his weapon rapidly during the attack on July 14, according to North Dakota officials.

North Dakota Attorney General Drew Wrigley said at a Friday news conference that the suspect, 37-year-old Mohamad Barakat, launched the attack after observing officers investigating a routine traffic accident. Barakat, who was shot and killed by another police officer during the incident, was not involved in the traffic accident.

Wrigley said that investigators found a stockpile of weapons, ammunition and parts to make explosives at Barakat's home. They also found he had searched the internet for terms such as "explosive ammo," "kill fast" and "mass shooting events," in addition to information about a downtown Fargo street fair.

The "binary trigger" device allowed Barakat to fire his double magazine long rifle very rapidly, according to Wrigley.

The attack was "all made possible because of what is known as a binary trigger," he said. "Everything you hit, you'll hit twice, because you got the binary trigger."

"None of the officers even had so much as an opportunity to turn, to crouch, to grab for their service weapon. Nothing," Wrigley went on. "It's that rapid."

Police identified the deceased officer as Jake Wallin, 23, in a Saturday news release. Officers Andrew Dotas and Tyler Hawes both sustained gunshot wounds, according to the release.

A 25-year-old woman was also shot during the incident and was transported to a health care facility with "serious injuries," according to the release.

Barakat was shot by officer Zachary Robinson during the incident. He was transported to a hospital and later died of his injuries, the release says. Robinson is on paid administrative leave pending an investigation into his use of force, as is standard operating procedure in Fargo, according to the release.

Wrigley said authorities are not releasing the police body camera footage at this time, citing the ongoing investigation, but that they would eventually.

Investigators still haven't determined a clear motive for the shooting, he added.