CHICAGO (AP/The Blaze) — Three Chicago teenagers accused of fatally beating a disabled man and posting video of the attack on Facebook were playing a game that involved finding an innocent victim and trying to knock him out with a punch, investigators alleged in court documents released Monday.

Delfino Mora, a 62-year-old father of 12, was attacked in an alley last week while searching for cans that he collected to make extra money for his family. Authorities said one of the teens punched Mora, who hit his head on the concrete, as the others filmed the attack with a cellphone. They then robbed him of $60.

Malik Jones, Nicholas Ayala and Anthony Malcolm Arrested in Connection With Brutal Beating and Murder of Delfino Mora

Delfino Mora

All three are charged as adults with first-degree murder and are being held without bond.

The trio — 16-year-old Malik Jones, 17-year-old Nicholas Ayala and 18-year-old Anthony Malcolm — decided “to play the pick ‘em out and knock em’ out game” when they saw Mora in the alley during the early morning hours of July 10, Cook County prosecutors allege in court documents.

Jones allegedly started the recorder on his cellphone, handed it to one of his co-defendants and told them he was going to knock Mora out, in a game CNN described as “pick ‘em out and knock ‘em out.” Prosecutors said the video shows that the teens surrounded Mora and asked if he had any money in his pockets. After Jones asked him a second time, he punched Mora in the jaw.

Malik Jones, Nicholas Ayala and Anthony Malcolm Arrested in Connection With Brutal Beating and Murder of Delfino Mora

Nicholas Ayala (left) and Anthony Malcolm (right)

Mora, who did not have complete use of his right arm because of a construction accident several years ago, fell to the ground. Prosecutors said the video shows Mora striking his head on the ground and the “loud crack of his head hitting the cement.”

The three teens then ran off, but Jones returning a short time later — and, with a bleeding Mora lying on the ground, pulled Mora’s wallet out of his pocket and took $60.

“All three leave the area laughing about victimizing the old man,” prosecutors contend in the court filings.

Mora wasn’t discovered until hours later by a person passing by. He died Wednesday at a hospital, and the Cook County medical examiner’s office determined that the cause of death was blunt head trauma.

Police arrested the three after learning about the video that was posted on Jones’ Facebook page, where it was spotted by a man who recognized Jones as the person who attacked him last month, authorities said.

Jones was still carrying the cellphone when he was arrested, prosecutors said.

“I never knew there could be people this cold,” said Mora’s 20-year-old son, Emmanuel, who said he has had difficulty sleeping and has had nightmares since he watched the video.

Prosecutors said Jones admitted that he punched Mora, Malcolm acknowledged videotaping the incident and Ayala admitted to his involvement in the incident.

A phone message left by The Associated Press for Jones’ mother was not immediately returned Monday, but his father told the Chicago Sun-Times that his son didn’t realize the punch was fatal.

“He was only trying to knock him out,” said Terry Jones, adding that his son’s troubles dated to his joining the gang and time he spent in juvenile detention.

A family friend of Malcolm’s, Melvin Corhn, said the family was saddened by Mora’s death but noted that Malcolm did not touch Mora, saying: “He did not hit him, he was just videotaping what was going on and laughing about it.”

A phone message was left at a phone listing for Ayala.

“It feels to us like they’re making fun of my dad because he couldn’t defend himself,” Mora’s 17-year-old daughter, Angelique, told the Chicago Tribune. “They think posting a violent video makes them look tough. It’s like they want to get famous.”