The tattooed sex offender nabbed on an L-train platform for the alleged murder of an elderly Florida man said Friday that he was responsible for 32 slayings.

After waiving extradition to Florida in Manhattan Criminal Court, Nicholas Gibson, 32, made the sick claim as US marshals escorted him to a waiting car to transport him back to Miami.

A reporter asked the convicted rapist, who has dubbed himself “Brent Savage” on the Web, whether he had murdered 77-year-old Erik Stocker in Florida.

“With my bare hands,” claimed Gibson, sporting a series of face tattoos, including the word “Freedom” inked over his right eyebrow.

As the shackled prisoner methodically swapped the excess of his waist chain from one hand to the other, he said he used a “big sword” to slaughter Stocker because his victim “wanted to go.”

A reporter asked how many people Gibson had killed.

After a long pause, the ex-con coolly stated, “32.”

Gibson had already allegedly confessed to the grisly slaying of Stocker — and claimed to have been behind six other murders in Florida, California and Georgia stretching as far back as 1999, according to the Miami Herald.

Authorities said they had physical evidence to corroborate Gibson’s confession to Stocker’s murder — but they appear less convinced that his additional claims are true.

“We are evaluating the information he has provided,” the Miami Beach Police Department said in a statement. “We will be working with law enforcement in these locations in an attempt to determine the credibility

of his statements.”

Stocker’s mutilated and decomposed body wasn’t discovered until April 30, at least 10 days after the murder, when neighbors complained of a foul odor emanating from his apartment.

A source told the Miami Herald it was an “unusually gory scene.”

Miami authorities quickly zeroed in on Gibson as a suspect and tracked him to Manhattan.

Authorities believe Gibson worked for Stocker as a home health aide, the Herald reported.

Gibson was wanted in Stocker’s slaying when two NYPD transit cops recognized him May 5 on the southbound L train platform at Union Square from a photo alert on their department iPhones.

When the officers tried to take him into custody, he became combative and was eventually booked on charges of resisting arrest, obstructing governmental administration and as a fugitive in another state.

Gibson has served extensive prison stints, including seven years for an aggravated sexual assault conviction in Illinois in 2000 and another four years in 2008 for having sex with an underage girl.

At the time of his subway arrest, he also was wanted for a parole violation for failing to register as a sex offender.

He has repeatedly been busted in various jurisdictions for failure to register, court records show.