TULSA, Oklahoma - Security video shows an off-duty Kiefer police officer saving a bicyclist from possibly being shot.

Brennon Lovett admitted to police he's killed one person and shot half-a-dozen more. The officer believes the bicyclist would have been the next victim.

Officer Martin Ramos was working security at a health clinic near 3rd and Lewis when he spotted Lovett pointing a gun at a man walking with his bike.

Security footage shows a man throwing down his bicycle and running off; what happened out of the frame is terrifying.

Ramos said Lovett pointed a gun at the man and fired one shot.

"I think he would have kept shooting if he hadn't seen me with the gun pointed at him," Ramos said.

The Kiefer police officer also works security at the Community Heath Connection. Six days ago, he was walking around the building when he spotted Lovett.

Video shows him in walking up to the man with the bicycle.

Ramos said, "He approached him and he asked him if he can walk with him and help him out in the alley because he has something heavy to lift."

The officer said the man refused to go into the alley.

"They go apart and he tried to shoot him in the back," Ramos said.

He spotted Lovett just in time.

The officer said, "I yelled, ‘what are you doing? Stop!’ That's when he released the shot, then, he looked at me. He lowered the gun and he ran.”

The ensuing chase ended with Lovett behind bars.

While being questioned, detectives said he admitted to murdering Wayne Bell in his driveway three years ago, and also confessed to several additional shootings.

Ramos said he normally doesn't wear a bullet-proof vest when working security, but, from now on, he will.