PITTSBURGH -- Authorities said a Pittsburgh man brutally beat his girlfriend's son to death because he hadn't vacuumed their Knoxville apartment.

Investigators said 11-year-old Donovan McKee endured nine hours of abuse Saturday before his mother returned to their apartment at the Rochelle Towers on Knox Avenue after work. The woman found her son unresponsive and called police.

When paramedics arrived, they said Donovan had a head wound and didn't have a pulse. Emergency responders did CPR and Donovan regained a slight pulse, but he died a short time later at a local hospital.

Anthony Bush, 29, was taken into custody and arraigned Sunday on homicide and child endangerment charges.

The complaint said that Bush admitted to police on the scene, “I did it. I did it.”

Police said Bush was watching Donovan and another child when he beat the boy with wooden sticks.

“During the beatings, at times, the sticks would break and Bush would order Donovan to clean up the pieces of the broken sticks,” the criminal complaint said.

Bush stated that he would take breaks, get new sticks and continue beating the child throughout the day, the complaint said.

At one point, police said Bush used a needle and thread to close a cut he'd caused on Donovan’s arm.

A neighbor who did not want to be identified told Channel 11 News she wishes she could have helped.

"If I had heard any type of noise coming out of there from the little boys, I would have right away called police, because you never heard nothing coming from the apartment,” the woman said.

Other neighbors said they are sickened by the news of the boy's death.

"I see his face and it's just heartbreaking," said Stacy Miller. "He was special. He was good. He knocked on my door every day and said, 'Miss Stacy do you need something from the store? Do you need me to take your garbage out? Do you need me to check your mailbox?'"

Donovan's aunt spoke to Channel 11's Timyka Artist on Monday. She said her family never approved of her sister's boyfriend. Crystal McKee said her sister met Bush 10 years ago when he had no place to go.

McKee said there were early signs of trouble including a time when she said Bush broke her sister's jaw during an argument. McKee said the abuse is likely the reason why she and the rest of her family weren't allowed inside of her sister's home.

McKee said she considers her nephew's death both tragic and preventable.

 Police said Bush told the boy's mother to tell police Donovan fell out a window, but she refused to lie about what happened.

Bush is being held without bail at Allegheny County Jail.