"If they would have taken him off the force in November 2008, that incident with my son would have never taken place," Delilah Quintana, mother of John Crespin, said. "It would have never happened. My son would have never been beaten that bad. But they failed to do their jobs."
Crespin had a run in with Sellers in Jan. 20, 2009. That was just two months after Sellers confronted volunteer firefighter Jared Lunn in lower downtown Denver on Nov. 23, 2008.
Crespin claims Sellers pulled in his driveway behind him and asked him to get out of the car. When Crespin complied, he says his shoulder brushed Sellers arm and says the officer flew off the handle.
Crespin says Sellers first ripped off his necklace, put him in a chokehold, and then lifted him 3 feet off the ground with nothing but his police baton. Sellers allegedly let Crespin fall to the ground face first. Then, Crespin says Sellers pulled him over the police car and hit him.
"He started punching me in the sides while I was already handcuffed. He was punching me in the sides," Crespin said. "I told him to quit, quit and he wouldn't quit. He did it one more time and he grabbed my face and said, 'Who the F do you think you are?'"
Crespin, who did not have a criminal history, was charged with felony menacing. He pleaded guilty to the charge in June 2009 and received probation. Crespin maintains he only pleaded guilty because he was afraid of going to jail and not seeing his new baby.
The Denver Police Department has not yet responded to requests by 9Wants to Know to learn if the internal investigation is open or closed or what the findings might be. Sellers is currently on leave with the police department.
The case involving Sellers and Lunn was reopened Monday hours before Denver Manager of Safety Ron Perea submitted in his resignation.
Lunn claims Sellers assaulted him after he told the officer to do his job and arrest someone. Lunn claims Sellers choked him, handcuffed him and then screamed obscenities words at him in front of a dozen witnesses in front of a downtown Denver restaurant.
In both cases, Sellers has said in court, or through attorneys, he did not hit anyone or was not involved at all.
Denver Police Chief Gerald Whitman would not specifically address any specific cases on Tuesday because they are under investigation. He did say there valid reasons and times that officers need to use force to get someone under control or arrest.
"Sometimes officers have to defend themselves, go hands on and it's not real pretty if you're in a fight," Whitman said. "And not a lot of people have been in those situations."
If you have any news tips or video, please e-mail Deborah Sherman at Deborah.Sherman@9NEWS.com.
(KUSA-TV © 2010 Multimedia Holdings Corporation)