Bizarre new details emerge in fatal stabbing at luxury NYC apartment building

Bizarre new details emerged Sunday in the murder of a man in a ritzy Long Island City apartment building  — with him found dead sitting upright in a bathtub and cops taking a naked man into custody.

Cops responded to the luxury Hayden high-rise building in Queens just before 1 p.m. Saturday after security responded to a fire alarm on the roof and spotted a naked man using a fire extinguisher to douse surveillance cameras and then trying to bust into an apartment there, law-enforcement sources said.

The NYPD put the man in cuffs and checked on the apartment he tried to get into, sources said.

Inside, they made a grisly discovery: blood splattered in the bedroom and the bathroom — with the dead victim sitting up in his tub with multiple stab wounds to his head, face and chest.

He was pronounced dead at the scene.

Police have not filed charges in the case but have the naked man in custody and consider him a person of interest, sources said.

It is not clear what led to the horrific crime inside the building, a posh 51-unit structure in Court Square known as The Hayden.

According to listings, two-bedroom units in the building rent for upwards of $6,000 per month.

Cops have not identified the victim pending family notification, sources said.

Additional reporting by Steven Vago