The deranged killer who escaped from a locked mental ward in Queens is a reputed gang member who was repeatedly denied parole while locked up for a fatal shooting and a vicious subway slashing.

Raymond Morillo, 33, was busted in 1998 after he and accomplice used razor blades to attack two men on an N line subway platform in Astoria.

Both victims were “permanently disfigured” when Morillo and Ricardo Munquia sneaked up from behind and slashed them from ear to lip in retaliation for a fight one man had with Munquia’s younger brother.

Morillo, who lived in Corona at the time, shouted “La Familia” — the name of a vicious Hispanic street gang — as he ran away, according to the Queens DA’s Office.

While out on bail in that case, he was busted again in the murder of Jose Paulino, who was shot twice after a dispute with Morillo and four other gang-bangers.

After being convicted at trial in the slashing and sentenced to 7 to 14 years in the slammer, Morillo plea-bargained to manslaughter in Paulino’s death for no extra prison time.

Morillo, who has a teardrop tattoo on the left side of his face, was denied parole five times before maxing out his sentence in early December.

But he was deemed too dangerous to walk the streets and was sent to the nuthouse instead, a law-enforcement source told The Post.

Although he’s not wanted for committing any crimes, Morillo — who was reported missing by his social worker — is being sought as an “emotionally disturbed person,” the source said.

In a letter to the state Office of Mental Health, which runs Creedmoor, state Sen. Tony Avella (D-Queens) said he was “obviously concerned about this serious breach of hospital security and the potential risk it has created for my constituents who live nearby.”

Avella demanded “to be fully briefed in person by the agency on exactly what occurred including how much time passed before it was discovered that the patient escaped the secure unit, how and when were law enforcement authorities notified and how can this type of breach of security be prevented in the future.”

An OMH spokesman declined to discuss Morillo’s escape, but issued a statement saying that “policy and regulations require…a thorough investigation to determine root causes of serious adverse events and, when appropriate, to require policy changes be made to prevent reoccurrence.”

Spokesman Ben Rosen also noted that state law gives mental patients a “statutory right to visitors,” as well as the right “to wear their own clothing while in treatment.”