FIRESTONE, Colo. -- A Firestone man, whose 6-year old dog apparently mauled his aunt, is facing possible charges of unlawful ownership of a dangerous dog and obstructing a police officer.

David Riley, 41, was arrested Saturday following the attack that left Myrna Lee, 54, with severe facial injuries. Riley was also treated for injuries he suffered when he tried to stop the dog attack.

“My sister went over to talk to him to get him to turn his radio down,” said the suspect’s mother, Jackie Riley. “I don’t know what happened.”

Neighbor Carlos Medina told 7NEWS that he heard the victim screaming, then saw her in the yard with blood pouring down her face.

“There were puncture wounds everywhere, mostly on her head and neck,” Medina said.

According to the arrest affidavit, the responding officer heard yelling and walked into the back yard where he saw the victim rocking back and forth moaning.

The officer said he commanded Riley to take the dog into the house, but the suspect did not respond.

The affidavit states that Riley appeared to be having difficulty holding the dog, a bull mastiff named Scout.

The officer said he had Scout at gunpoint and heard the victim yell several times, “shoot the dog, shoot the dog.”

Police said the suspect finally got the dog into the house.

After attending to Lee, who was transported to the Medical Center of the Rockies, officers asked Riley to come out of the house. They said he refused.

Police said Riley turned out the lights.

The affidavit states that when one of the officers knocked on the glass door and commanded Riley to come out, Scout and another dog, named Angel, charged the door.

The officer said they were barking and growling.

Neighbors told 7NEWS that both Scout and Angel have been involved in several attacks.

“I don’t trust those dogs,” Medina said. “They’ve attacked before and they’ll probably attack again.”

Jackie Riley told 7NEWS the attack, as bad as it was, needn’t have happened.

“I called police earlier in the day,” she said. “To get help with my son, to put him in detox because I had a feeling that the day wasn’t going to go very good.”

Jackie Riley said the officer didn’t help.

Firestone police Chief David Montgomery declined comment, saying the case had already been turned over to the district attorney.

A spokeswoman at the District Attorney's office said they’re trying to determine whether additional charges are warranted.

The dog in question was taken to the Humane Society of Weld County.

The executive director, Elaine Hicks, said it’s not the first time Scout has been there.

“He was here approximately a year ago for biting an 8-year old child,” she said. “He’s a very dangerous dog. He’s so dangerous that I won’t let my staff near him.”

When asked why a dog that’s been involved in so many attacks has been given back to the family, Hicks said, “These are all very well documented cases, so I’m at a loss as to why this particular animal, given its history, is returned to the owner.”

Jackie Riley said “It’s because he (her son) has not been found guilty of all the accusations.”

Riley has an extensive record in Weld County, listing arrests for disorderly conduct, resisting arrest, criminal trespassing, criminal mischief, and several traffic arrests.

Among the previous court cases involving Riley and dogs he owned:

Sept. 3, 2004: Three boxers attacked a Firestone resident while she was walking her own dog. Riley was charged in a Weld County Court, but the dogs were later returned to Riley.

Sept. 23, 2004: The same three boxers, taken to an animal hospital after the attack, mauled a dog handler, who was seriously injured.

May 9, 2005: A boxer owned by Riley attacked a Dacono woman, biting her neck. Riley had been released from jail a week earlier after serving time in connection with a previous attack involving one of his dogs.

Riley is due back in court on Friday on the latest charge.