The body of a 19-year-old homeless woman was found Saturday wrapped in plastic and stashed in the abandoned Fulton Fish Market building in lower Manhattan, according to police and law enforcement sources.

The dead woman’s boyfriend and another pal found her corpse on the second-floor staircase of 95 South St. near the F.D.R. Drive at around 9:20 a.m., cops and sources said.

They called 911 when they found her, the sources said.

The woman’s boyfriend claimed to cops his significant other “had been led” to the warehouse weeks ago, the sources said. Police could not immediately verify whether his claim was true.

The boyfriend was not considered a suspect as of Saturday evening, police said.

“Right now, we simply don’t know what happened. We are waiting for the M.E. [medical examiner] to tell us,” an NYPD spokesman said.

Locals said homeless people have long since taken over the building — once a vital part of the South Street Seaport’s bustling fish market, which relocated to the Bronx in 2005.

“For years now,” one area resident said about how long the problem has endured.