NEW YORK (CBSNewYork) — Police late Wednesday were interviewing a man in connection with a terror alert that went out to all officers earlier in the day.

As CBS2’s Dave Carlin reported, a citywide warning went out to every NYPD officer earlier the day, in light of two phoned-in threats – one of which was described as ISIS-related.

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The NYPD was first contacted by Philadelphia police after they received an anonymous tip that someone wanted to shoot a police officer there, 1010 WINS’ Juliet Papa reported. Philadelphia police traced the call to an address in Upper Manhattan, NYPD Chief of Intelligence Thomas Galati said.

The NYPD 32nd Precinct stationhouse in Harlem then received an anonymous call indicating someone was going to shoot an officer in New York City, Papa reported. A reference was made to ISIS in that call.

“One of the phone calls indicated ISIS. Not the phone call to Philadelphia but rather the phone call to New York,” Galati said. “We are taking it serious based on what happened in Philadelphia a couple of weeks ago.”

Every officer was sent photos of one specific man – Marcus Shelton, 36.

Police said Shelton has a criminal history, but he is not officially a suspect in any threat case. He is merely someone police say they want to “have a conversation” with.

Speaking to Rich Lamb in a WCBS 880 event Wednesday evening, NYPD Deputy Commissioner of Intelligence and Counterterrorism John Miller said the man was being held late Wednesday.

“We located him today. We had a couple of warrants outstanding on him for other alleged past crimes. He is in custody now, and we’re pretty close to determining that he does not pose a threat to police officers,” Miller said. “We’re a little less close to determining exactly where that phone call came from or what the motive behind it was.”

Police sources told CBS2 they do not believe Miller made either phone call, but said his name was mentioned by the person or persons who called in the tips.

The actual caller is known to the NYPD, Galati said, adding the person has several addresses in New York and a criminal record, WCBS 880’s Marla Diamond reported.

Sources also told CBS2 Shelton was not the person who made the phone calls to Philadelphia police and the NYPD, but rather the person that the caller claimed was allegedly making the threats.

Shelton was ordered held on a parole violation and outstanding warrants, and he will be held until the warrants are clear, sources said. He surrendered earlier Wednesday to New York State parole officers in the Bronx and was later questioned by the NYPD, sources said.

He was expected to appear in Bronx Criminal Court before a judge to satisfy outstanding warrants.

Miller stressed the alert about the threats was directed at police officers, and not the public at large.

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“This investigation is still at that stage,” Miller said.

Speaking to Lamb, Miller emphasized the importance of erring on the side of caution in such a scenario as the one that unfolded earlier in the day.

“I’ve got to say, when you get a call like this, you have to ask yourself three or four questions. One, is the person calling themselves? Two, is somebody calling specifically for the purpose of setting them up? Is it some kind of prank, or is it a real warning?” Miller said. “And given the events in Philadelphia last week where you saw the attempted assassination of a police officer, or the events that we saw in New York with officers (Rafael) Ramos and (Wenjian) Liu, while you sort through those possibilities, you have to take it seriously.”

Police Commissioner Bill Bratton said officers with smartphones and tablets received the information immediately. When such threats occur, technology works to the advantage of the NYPD, Miller said.

“Every police officer in New York City has a department-issued smartphone,” he said. “In the old days, we would have had to put out the equivalent of a teletype and read it at roll calls, and you know, try to make Photostats of pictures. We were able to blast out this ‘be on the lookout’ to 20,000 police officers within a couple of minutes of putting together the clues here.”

The threat comes after a Philadelphia police Officer Jesse Hartnett was shot by a suspect who identified himself as an ISIS sympathizer on Jan. 7. Hartnett was ambushed while in his squad car and shot in the arm.

The FBI and Philadelphia police have been investigating claims that the suspect, Ed Archer, was part of a larger terror plot and that the threat to police was not over, CBS2’s Andrea Grymes reported.

“We are taking it serious based on what happened in Philadelphia a couple weeks ago,” Galati said.

Archer allegedly told investigators he is an ISIS sympathizer.

“The perception is that there’s a war on police,” said retired NYPD Detective Sgt. Joseph Giacalone. “That’s the perception by cops everywhere.”

Giacalone now consults with and trains police officers. CBS2’s Carlin asked him what advice he would give experienced officers, as well as new ones just coming into the department.

“Don’t have your head buried in the phone,” Giacalone said. “When they want to take their break, they need to go somewhere — maybe go back to the stationhouse. Go to a location where you don’t have to worry about somebody sneaking up behind you right now.”

Patrolmen’s Benevolent Association President Patrick J. Lynch also urged officers to be cautious.

“New York City police officers recognize that they are always a potential target for terrorists and political extremists,” Lynch said in a statement. “The PBA is reminding all of our members to be alert at all times, back each other up and to take all necessary precautions when responding to jobs. Be mindful that any call, regardless of how insignificant it appears to be, may be a set up. 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.”

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Police are not releasing the identity or description of the caller.