No charges will be filed against nine police officers who fatally shot an armed bank robbery suspect on the Montpelier High School athletic field in January, authorities announced Tuesday.

An hour and a half after Nate Giffin, 32, robbed a nearby bank, police shot him, firing 21 to 23 rounds. Authorities said Giffin repeatedly raised his gun, even after being wounded. It turned out to be a BB pistol.

Giffin, a Burlington resident, repeatedly threatened police and made suicidal statements, Attorney General T.J. Donovan said. Giffin pointed his weapon at officers who had scrambled to the school, which was in session. Students were put on lockdown.

"I'm not going back to jail, so something is going to happen," Giffin told officers during the hour-long standoff. He made other statements, such as "Are you guys ready? We're going to rock and roll," and "Tell my dad I'm sorry," according to authorities.

Donovan and Washington County State's Attorney Rory Thibault deemed the officers' actions lawful. The officers who fired were State Police Sgt. Lyle Decker, Trooper Christopher Brown, Sgt. Cory Lozier, Sgt. Eugene Duplissis, Sgt. Charles Winn, Sgt. David White, Trooper Brandon Degre, Trooper Isaac Merriam and Montpelier Police Cpl. Michael Philbrick.

At a press conference, Vermont State Police Col. Matt Birmingham announced several steps, including the deployment of additional nonlethal weapons and enhanced training, intended to prevent similar occurrences. However, Birmingham cautioned, that doesn't mean troopers will use nonlethal options in all confrontations.

A report released by Donovan portrayed Giffin as intent on instigating a confrontation. The report gives the following account:

Around 9:30 a.m. on January 16, Vermont State Employees Credit Union staff reported an armed robbery. The school resource officer at Montpelier High School, Cpl. Matthew Knisley, heard the report and saw Giffin, who matched the suspect's description, running nearby. The school is across the street from the bank.

Knisley began chasing Giffin on the school grounds. Giffin refused commands to surrender and drop his pistol, and headed for an athletic field. Vermont State Police troopers soon arrived.

Around 11 a.m., Giffin walked toward a shed where three armed officers had taken cover.

One of them, Lozier, said, "What can we do to resolve this peacefully?"

"Nothing," Giffin responded. "Do you have a cigarette?"

"I don't," Lozier said. "Put the gun down, Nate."

"Absolutely not, I'm not putting this gun down for nothing. Do what you got to do," Giffin responded.

"Nate, we all want to end this peacefully," Lozier said. "Can you put the gun down for me?"

"Absolutely not. I'm not putting this down," Giffin said.

Giffin kept advancing. Lozier shot him once in the chest with his rifle. Brown fired four shots that apparently missed.

Giffin dropped his weapon and fell to his knees. He then picked up the gun and pointed it toward officers. Several of them fired 15 to 17 shots. After a few seconds, Giffin again raised the gun. Philbrick shot him once more.

Giffin was struck seven times.

Friends and family have described Giffin as a troubled man who repeatedly tried to straighten out. He had a lengthy criminal record, and went to prison for an armed robbery at the Randolph National Bank in Williamstown in 2011. Monday, Thibault said Giffin was the suspect in an armed robbery at the TD Bank in Waitsfield in December.

Donovan said he spoke with Giffin's father on Monday night to inform the family of the decision.

"I didn't know Nate Giffin, but I'm sure he was a lot more than the last minutes of his life," Donovan said.