NYPD on Alert After Caller Says Ex-Con Wants to Kill a Cop, Pledged Allegiance to ISIS

An anonymous tipster called police saying a local man may be armed and said he wanted to kill a cop.

The NYPD was on high alert Wednesday after receiving a tip that a man who may have pledged allegiance to ISIS threatened to kill a police officer, a police source told INSIDE EDITION.

An anonymous tipster called the 32nd Precinct in Harlem saying a local man, identified by the source as 36-year-old Marcus Shelton, may be armed and said he wanted to kill a cop.

The caller also said Shelton, a Peekskill native who lives in the Bronx and is currently on parole for assault, may have associated himself with the Islamic State, the source said.

Shelton surrendered himself hours later and was taken to court to answer two open warrants on parole violations, according to reports.. He was unarmed and turned himself in without incident.

"We know who this individual is and we're actively looking for him right now," Thomas Galati, chief of the NYPD Intelligence Bureau, had said at a press conference before Shelton turned himself in..

Read: Authorities: Cop Shot Dead By Man Who Allegedly Went 'Looking to Kill An Officer'

“We’re only looking for him to speak with him about this threat," Galati continued. "This isn’t a probable cause to arrest at this time. We just need to find him and have a conversation and then continue with the investigation.”

A bulletin—known as an Officer Safety Alert— was issued to officers to remain vigilant as the matter is investigated. 

But Shelton's father told the New York Daily News that his son would never hurt a police officer, as his late brother, Jason Paige, served as a Marine and a city cop. 

“I’m glad he turned himself in and that he’s cooperating with authorities,” Jason Paige, 72, told the News.

Officials had first learned of a threat on Tuesday when Philadelphia Police contacted the NYPD saying they received an anonymous phone call about a man plotting to shoot a cop there. There was no mention of ISIS in that phone call, Galati said.

The call was traced to an address in upper Manhattan.

This threat comes weeks after a Philadelphia police officer was shot three times by a gunman who allegedly pledged allegiance to the Islamic State.

Read: NYPD Police Officer Dies After Being Shot in the Head During Gunfight

Officer Jesse Hartnett, 33, was driving in his marked police cruiser through West Philadelphia late Jan. 7 when he was shot at 13 times in what Philadelphia Police Commissioner Richard Ross called an attempted execution.

The suspect, later identified as 30-year-old Edward Archer, allegedly confessed to the act “in the name of Islam,” authorities said.

Galati acknowledged the Philadelphia attack in the NYPD’s handling of the New York threat, saying Wednesday: “We are taking it serious based on what happened in Philadelphia a couple of weeks ago.”

Patrick Lynch, president of the NYPD’s PBA, warned officers to treat every call with caution.

“Be mindful that any call, regardless of how insignificant it appears to be, may be a set up,” Lynch said in a statement. “Rely on your training and tactics and trust your instincts. Don't hesitate to call for back up when your gut tells you something is wrong."

Watch: Attacker Who Ambushed Cop Told Investigators 'I Did It In The Name of ISIS'