By Matt Petrillo

PHILADELPHIA (CBS) – Police are searching for clues to bring closure to their brother in blue. The son of a Philadelphia police chief inspector was shot and killed in FDR Park on Saturday. The reward is growing for anything that will lead to an arrest in the death of 20-year-old Nicholas Flacco, the son of Internal Affairs Chief Inspector Chris Flacco.

The reward has grown to $36,000 for information leading to an arrest.

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On Sunday, FOP Lodge 5 President John McNesby pleaded for information about the shooting that took Flacco’s life.

“Somebody saw what happened there last night,” McNesby said. “Somebody should bring them forward.”

Sources told Eyewitness News that Flacco was celebrating the Phillies’ win with friends in FDR Park around 10 p.m. on Saturday. That was when a fight broke out. A man then pulled out a gun and opened fire, leaving Flacco for dead.

“We don’t have any idea what role this male played in it. All indications are that the people out there did not know him. There is no suggestion that he was involved in the initial argument, whatsoever. That is what makes it even more confusing. So, again, there are a lot of things that we don’t know. There is no indication right now that Nicholas Flacco was involved in any physical confrontation,” said Philadelphia Police Commissioner Richard Ross. “It appears that this individual deliberately fired a round into his chest and took his life.”

“It makes no sense at all,” McNesby said. “Beautiful day yesterday. Everybody was down there at the Phillies, enjoying themselves. It could be culpability anywhere, but there’s no reason to shoot anybody.”

Friends said Flacco attended Penn State University. He was home over the weekend to celebrate his birthday.

Instead of planning his future, Flacco’s family is planning his funeral while police search for the killer.

“It’s a sad thing. It’s a senseless thing,” McNesby said. “Bring them in and you’ll get paid today, please.”

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At this point, police have not released any information about a suspect.

Police are urging anyone with information to call Philadelphia Homicide Unit at 215-686-3334 or 215-686-TIPS.