Police launched a massive manhunt Tuesday for a violent sex offender and career criminal sought in the horrific Queens fire that killed the elderly parents of an FDNY paramedic.

Jamel McGriff, 42, an ex-con on parole with a string of career busts, has been identified as a suspect in the vicious deaths of 78-year-old Maureen Olton and her husband, Frank Thomas Olton, 76, who was found bound to a pole in the basement with multiple stab wounds after their Bellerose home was torched Monday, police and law enforcement sources said.

NYPD Commissioner Jessica Tisch said McGriff is “armed and dangerous” and has a 30-year-long criminal record.

“The suspect’s MO is to go door to door, asking for some kind of assistance until he can gain entry,” Tisch told reporters Tuesday.

“Investigators for the NYPD and our partners on the Regional Fugitive Task Force are working around the clock to locate and to apprehend Mr. McGriff,” she said. “We appreciate the public’s and the media’s assistance here.”

Tisch said the suspected killer entered the 254th Street home through a backdoor around 10:15 a.m. Monday – and was caught on surveillance footage leaving after terrorizing the elderly victims for nearly five hours.

Frank Olton had been doused with a flammable liquid and set on fire, while both victims were stabbed multiple times, sources said.

Just 14 minutes later, fire alarms went off and firefighters responded to the blaze.

Maureen Olton’s body was found on the first floor, and her husband in the basement, where he had been chained and lifeless before the fire was set, the sources said.

Tragically, police said their first responder son was alerted to the blaze at his parents’ home and was at the scene when the fire was doused.

McGriff spent nearly 17 years of a 20-year sentence in state prison on a 2006 robbery, sex act and assault conviction — and was still on parole following his release in 2023, state correction records show.

McGriff had robbed a 34-year-old man at knifepoint on an F train on Nov. 12, 2005, snatching a $200 watch and $40 in cash, according to sources.

The fiend was also convicted of molesting a 23-year-old female employee at knifepoint inside a business on 16th Street and Seventh Avenue on Nov. 21, 2005 and was due to be on parole until at least next year. He had also stolen about $300 from the store, cops said.

He was arrested Dec. 2 of that year and charged with criminal sex act, burglary, robbery and sex abuse.

However, police said he remained free despite failing to register as a sex offender following his release, and is the prime suspect in at least two robberies in the Big Apple since he was freed.

In July, he allegedly walked into a GameStop on 125th Street in Manhattan with a gun and made off with cash, NYPD Chief of Detectives Joseph Kenny said Tuesday.

On Aug. 31, McGriff allegedly forced an employee at a Verizon store on Sixth Avenue into a back room at gunpoint — only to have the victim notice it was a fake gun and chase him away.

It is not clear why McGriff was not jailed on a parole violation despite the sex registry violation and the suspected robberies.

Officials at the state Department of Correction and Community Supervision did not immediately respond to a request.

“[McGriff] had been checking in regularly [with his parole officer,]” Kenny said. “And this parole officer actually did a great job for us, not on one, but on two occasions, because he also did the identification for us for the robbery that took place in the confines of the 13th Precinct, which was the Verizon store.”