JOSEPHINE, Texas (CBSDFW.COM) – CBS11 News has obtained exclusive body cam video of police officers in a small Collin County town desperately trying to stop a man from killing their police chief Mathew Briggs.

The video shows officers in Josephine approaching and shooting a man with a rifle at the city hall building last September.

screen shot 2017 09 21 at 5 54 18 pm Body Cam Video Of Confrontation To Keep Gunman From Killing Texas Police Chief Released

AK-47 at scene of Josephine City Hall shooting (Chopper11)

On Monday, that man went before a judge where he was sentenced to 16 years in prison and 10 years probation after pleading guilty to two counts of aggravated assault with a deadly weapon on a police officer.

The evidence was riveting body cam footage of a man on a mission to kill the town’s police chief.

The 62-year-old man, Bobby Chamberlain, was reportedly incensed after being previously arrested for punching a Josephine officer.

abobby Body Cam Video Of Confrontation To Keep Gunman From Killing Texas Police Chief Released

Bobby Chamberlain

Minutes later on that day last September, officers received word Chamberlain was approaching city hall in the small Collin County town with a rifle.

In body cam video obtained exclusively by CBS11 News, officers confront the man who shouts obscenities.

Officers repeatedly try to end the standoff without firing shots.

At one point, Chamberlain raises his rifle but then lowers it again forcing officers to shoot.

The chief and one of his officers left the courthouse today without commenting after Chamberlain was sentenced to 16 years in prison and 10 years probation.

His attorney called it a fair sentence.

“It was quite an emotional case we worked real hard to try to get the best result we could it’s just the facts were really really damaging,” says Todd Shapiro, Chamberlain’s attorney.

Chamberlain was shot three times and still had to be dragged out of the back of a pickup truck by officers.

His wife and friends asked the judge Monday for leniency arguing that the man they knew simply snapped.

Chamberlain never shot anyone.

But the Collin County District Attorney’s Office hopes the prison sentence will send a strong message to anyone thinking about retaliating against law enforcement.

During a hearing in the 296th District Court, Collin County Prosecutor Doug Millican argued that Chamberlain deserved prison.

“Nothing has changed for him. All we have done is press pause on the situation. He has to be stopped. If he gets out, he will try to kill Chief Briggs, People fail on probation for a variety of reasons. Rarely do they fail because they lash out against the authority of the probation officers. That is exactly why he will fail if he is placed on probation,” said Millican. “Where others see righteousness, he sees injustice. Where others see help, he sees harm. Where others see authority, he sees oppression. That would be fine if he stayed at home. But that doesn’t scratch his itch. He has to confront the source of his anger with violence.”