Ronald Troyke had expressed a hatred of police and decided to try and kill as many as he could in Nevada on Friday.
The shooter Ronald killed three people in the rampage and a police officer also.
During the attacks he was approached by Johnathan Hurley who shot the cop killer five times, killing him.
Police were called to the scene and hero Johnathan who had taken the assault rifle off the gunman, was then shot dead himself by a officer mistakenly believing him to be Ronald.
Colorado officer Gordon Beesley was shot with a 12-gauge semi-automatic shotgun.
And the cctv footage showed the shooter returning to his vehicle and getting a Ar15 assault rifle, before being confronted by Johnathan.
Killer Troyke, who had described police as the “enemy” and “expendable” was seen driving his pick-up truck to an area near a library.
He drove past shops and restaurants in Arvada, about seven miles from Denver on route to the scene.
He gets out of the vehicle carrying a gun before proceeding to kill Beesley and shoot out the windows of police cars in the area.
After returning to his pick-up to retrieve an AR-15 rifle, Troyke was confronted by Hurley, who shot him with a handgun.
When another officer arrived, Mr Hurley was holding Troyke’s AR-15 and the responder opened fire, killing him, the local force said.null
A retail worker said Mr Hurley had been shopping when he heard shots and ran out of the store.
He did not hesitate – he didn’t stand there and think about it.
He heard the gunfire, went to the door, saw the shooter and immediately ran in that direction,
” Bill Troyanos told Denver TV station KMGH-TV.
Mr Hurley fired five or six shots and Troyke fell against a parked vehicle, Mr Troyanos added.
In a video statement, head of police Link Strate said Mr Hurley was a “hero” who had saved lives.
He did not offer an apology, however, describing Mr Hurley’s death as “equally tragic” to Gordon Beesley’s.
Mr State said: “The threat to our officers and our community was stopped by a hero named Johnny Hurley.
“Johnny’s actions can only be described as decisive, courageous and effective in stopping further loss of life.”
Police said a document written by Troyke suggested he planned to kill as many Arvada police officers as he could.
Troyke wrote: “We the people were never your enemy, but we are now.
“This is what you get – you are the people who are expendable.”
Mr Hurley’s family said they had received support from the city and police and are waiting for the outcome of a third-party investigation into the shooting.
Gordon Beesley had been with the department for 19 years.
Arvada Police said Beesley was a school resource officer at Oberon Middle School and was working patrol while school was out for the summer.
Arvada Mayor Marc Williams said Beesley had been named employee of the year, “because he went beyond the call and just was always there for folks.”
He was the epitome of what you would want in a police officer,” Williams said in an interview with FOX31.
“We’re so proud to have him as part of our force, because he truly exemplified the type of officers we have here in Arvada.”
Donations for Officer Beesley’s family and funeral expenses can be made through the Colorado Fallen Hero Foundation website. The Arvada Police Department has also set up a web form for people wishing to make non-monetary donations.