An 80-year-old man who was found dead in a Queens hot tub over the weekend is believed to have suffered a heart attack, police said on Tuesday.

The man, Hock Ma, was found face-up in the bath at about 6:20 on Sunday night inside Spa Castle in College Point. Police are waiting for the medical examiner to confirm the exact cause of death.

Spa Castle is modeled after a traditional European bath house, according to their website. The brand recently opened a 39,000-square-foot Manhattan location with a roof deck, hydrotherapy pools, a standing neck shower and a swim-up Aqua Bar on East 57th Street.