A Florida double murderer appeared with the word “killer” written on his teeth in court, where he proceeded to assault his own lawyer Monday.

Joseph Zieler, 61, beckoned his lawyer, Kevin Shirley, over to speak to him after entering court in handcuffs for a pre-sentencing hearing over the murders of an 11-year-old girl and her baby-sitter.

After leaning in to speak to him, Zieler — who was eventually given the death penalty — suddenly caught Shirley in the face with a violent elbow shot, sending him spinning, courtroom video shows.

As onlookers gasped, three bailiffs immediately subdued the tattooed Zieler, who was already in restraints, taking him down to the floor before removing him from the courtroom.

According to video shown by the Fort Myers News-Press, the attorney managed to somewhat keep his composure and return to his table.

Shirley then assured the judge he was OK and, as a former boxer, had sustained much heavier blows than the one Zieler had dished out.

Zieler, of North Fort Myers, carried out the 1990 attack by sneaking into a condominium and finding Robin Cornell, 11, and baby-sitter Lisa Story, 32, inside.

The child’s mother had gone to her boyfriend’s home for the night and returned to the Cape Coral apartment the following day to find her daughter and Story dead.

The victims had both been sexually assaulted and beaten before being suffocated, prosecutors said.

The case went cold for more than two decades before new DNA evidence tied Zieler to the crime in 2016.

He was already in custody for assaulting his stepson when he was charged with the double killing.

A jury convicted him of the slayings in May and recommended the death penalty earlier this month.

Zieler denied any connection to the crime and testified on his own behalf at his initial trial.

Lee County Circuit Judge Robert Branning formally sentenced Zieler to death Monday afternoon following the assault on his lawyer.

Jan Cornell, the slain chlld’s mother, was in court Monday and witnessed the attack on the attorney.