Police arrested 36-year-old Christopher Nelson Sunday after he allegedly harassed and threatened an off-duty police officer wearing a hijab in Brooklyn over the weekend in front of her 16-year-old son.

The cop, identified as Officer Aml Elsokary, had parked at about 5:50 p.m. on Saturday in Bay Ridge when she noticed a man bothering her teen son, a law enforcement official said. But when she intervened near the corner of Ridge Boulevard and 67th Street, the man started in on her. He called her an “ISIS b---h” and threatened to cut her throat, the official said.

Nelson, also of Bay Ridge, was arrested and charged with second-degree menacing as a hate crime and aggravated harassment to race and religion.

“Gr8 job by @NYPDDetectives from #HateCrime Task Force & Warrants in apprehending person wanted 4 BIAS incident against #Hero #Muslim officer,” the NYPD’s Muslim Officers Society tweeted Sunday evening.

Moments later, Mayor Bill de Blasio tweeted: “Aml Elsokary is one of 900 Muslim-Americans in @NYPDnews who protect us. Let’s stand with her family. Call 311 with any info. #NotInOurCity.”

The hate-filled attack is one a string of recent incidents. On Thursday, three apparently drunk men tried to rip off the hijab of an 18-year-old woman and shouted President-elect Donald Trump’s name at her as she waited for and then boarded a northbound 6 train at 23rd Street.