Police said they have been combing through hundreds of online postings and calls to 911 to try to determine if any threats are credible.
"All threats against members of the NYPD are taken seriously and are investigated immediately to determine the credibility and origin of the information. So far, we have assessed hundreds of online postings and calls to 911 and 311 that have resulted in more than 50 threat investigations, of which about half have been closed or referred to other agencies, the department said in a statement.
"Although, we have made nine arrests, officers are advised to remain vigilant at all times. Additionally, security measures will continue to be assessed and police resources will be deployed accordingly. However, we continue to ask that the public, upon becoming aware of any threats, immediately report the information to the police."
The most recent arrest was made on Friday at around 11:10 a.m. in Brooklyn, police said.
Michael Wallace, 26, of Brooklyn, is charged with a felony count of making terroristic threats, police said. No further information regarding the circumstances of Wallace's arrest was provided.
On Wednesday, 26-year-old Brooklyn resident Jose Maldonado was taken into custody after he posted pictures of weapons on Facebook with a caption threatening to kill two officers, 1010 WINS reported.
Maldonado is charged with making a terroristic threat, police said.
Elvin Payamps, 38, was also arrested and charged on Wednesday after police received a 911 call from a man who said he overheard someone talking on his cell phone about killing cops and saying he had guns at his home.
Police said they circulated a description of the suspect and started canvassing the area near 79-55 Metropolitan Avenue, where the call came from.
Payamps matched the description and was seen getting into a car nearby, police said. He was arrested after being spotted with a bag of marijuana, police said.
A search of his home turned up a shotgun, pistol, two bulletproof vests and brass knuckles, police said. Payamps faces weapons and drug charges.
Also facing charges for alleged threats are Tyrone Melville, of Manhattan; Roberto Labita, of Staten Island; Yasin Shearin, of Staten Island; Robert Bowman, of Manhattan; Devon Coley, of Brookln; and Jihaad Curry, of Queens.
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