Transcript for The murder of reputed New York mob boss Francesco Cali may not be mob related: Source
Next to the breaking developments in a criminal investigation getting a lot of attention back home. The NYPD now saying this man is behind the fatal shooting of an alleged mob boss. That suspect is in custody tonight. ABC's Kenneth Moton with the latest. Reporter: Tonight, sources telling ABC news the first murder of a reputed New York mob boss in more than three decades may not have been mob related. While we believe we have the shooter in custody for this incident, the investigation is far at this point from over. Reporter: New York City police plan to charge Anthony comello for the execution-style killing of Francesco "Franky boy" cali outside his Staten Island home this week. Police say the 24-year-old and his blue truck, spotted at the scene, were tracked down in brick, New Jersey. Confirmed, male shot. Reporter: Source says NYPD investigators believe the suspect had been dating a female relative of cali's when the reputed boss of the Gambino family told him to stop seeing her. We are well aware of Mr. Cali's past. That will be a part of this investigation as we determine what was the motive for the incident. Reporter: Police say the shooter slammed into cali's parked SUV while he was home. The two men, seen talking on grainy surveillance video, even shaking hands before the gunman opened fire. NYPD detectives say they got a big break, discovering a fingerprint on cali's bloodstained vehicle. Despite the new development, police are still concerned about potential retaliation. The prevention of any future violence is at the utmost on our minds. Reporter: NYPD says the suspect is being held in new Jersey for now and will be charged with murder in the coming days. Tom. Kenneth Moton with those new developments in the investigation.
This transcript has been automatically generated and may not be 100% accurate.