CHICAGO (CBS) — A nine-year old boy who was gunned down on the South Side was lured into an alley and executed in an apparent gang-related retaliation, Police Supt. Garry McCarthy said Thursday.

McCarthy, appearing at a news conference at the crime scene, said it was the most “abhorrent, unfathomable cowardly crime” in his 35 years of police work.

“Children get murdered because of somebody else’s involvement in criminal activity.”

“We are going to solve this crime,” he declared.

Citing sources, CBS 2 Mai Martinez reported earlier this week that Tyshawn Lee was targeted, possibly because of gang ties to family members.

Tyshawn was shot multiple times in an alley near 80th Street and Damen Avenue in the Gresham neighborhood.

“We need some help from the community, somebody needs to step forward” to solve this crime, McCarthy said.

McCarthy said police know which gangs were involved but police need a bit more information to make an arrest.

“A baby was executed; a baby was assassinated in this alley,” Father Michael Pfleger said. “We have gone to a new low.”

“We need to get this killer off the street.”

Pfleger reminded the community that there is a $35,000 reward for information that leads to the killer. He said he’ll pay out of his own pocket to relocate any resident who supplies authorities with information that helps catch the killer.

Investigators are looking into several possibilities that Tyshawn was targeted because of gang ties to his family. Tyshawn’s mother, Karla Lee, denied any gang connections within her family.

Tyshawn’s family and friends have pleaded with people to put down the guns, but in a photo we’re choosing not to show, Tyshawn’s mother posed with a gun held to her lips as if to blow imaginary smoke off the barrel.

Police sources say Tyshawn’s father has gang ties. The father stood near the news conference and spoke with police for about 10 minutes. He denied statements by McCarthy that he has been uncooperative with police.

“I don’t have no enemies. I’ve got friends and family,” he tells WBBM Newsradio.