The NYPD detective ruthlessly stabbed by an illegal migrant during a Bronx robbery ripped a Halloween-like mask off one of his callous attackers while fighting back, sources revealed Wednesday — as both fugitives were ordered held without bail.

Sneider Mejia, 24, donned the rubber flesh-colored mask with a pronounced nose when he and D’Angelo Caraballo, 25, allegedly ambushed off-duty Det. Jose Mercedes as he cleaned out the trunk of his car Friday afternoon in Norwood, law enforcement sources said.

Mejia allegedly drove the scooter that brought the pair to the scene, before a shirtless Caraballo allegedly stabbed Mercedes.

During the melee, Mercedes defended himself, tearing off Mejia’s sinister face covering, the sources said.

The 44th Precinct detective, a 10-year veteran of the department, survived the vicious attack because the blade – that left him with at least seven wounds to his neck and leg – miraculously missed his vital organs, sources said.

He was released from the hospital to salutes and raucous applause Monday.

Both suspects – identified by the feds as illegal migrants from the Dominican Republic – were found by the US Marshals Service hiding in a basement of a home in Lynn, Massachusetts and taken into custody overnight, the NYPD said Wednesday.

They will be brought back to New York City to face attempted murder charges, the department said.

Both were ordered held without bail during their joint appearance in Lynn District Court Wednesday.

Mejia was bare-faced without his distinctive mask and stood stony-faced in the courtroom with a Vale Sport sweatshirt bearing the number 14. Caraballo wore a Prestige hoodie emblazoned with a flashy graphic of a woman.

They will be brought back to New York City to face attempted murder charges, the NYPD said.

Both men entered the United States illegally during the Biden administration and Caraballo had been arrested for various crimes in New York – but was released.