A man who murdered an 11-year-old girl and the person babysitting her has exploded in court, whacking his own lawyer in the face before being tackled to the ground.

Double murderer Joseph Zieler showed up to a pre-sentence hearing in a Florida courtroom with the word “killer” on his teeth.

As his lawyer was leaning in to say something, Zieler, while wearing handcuffs, whacked his lawyer in the face with his elbows.

Florida double-murderer Joseph Zieler appeared to want to whisper something in his lawyer’s ear before he attacked him in court. Photo / Fox 4

His lawyer, 61-year-old Kevin Shirley, was caught off guard and went falling back.

Police officers then tackled Zieler to the ground before forcibly removing him from the courtroom.

Shirley told Fox 4: “It seemed like he didn’t want our conversation to be picked up by the microphones. So he waved me down and I bent over, and he struck me. The bailiffs were extremely quick to respond and eliminated any future threat.”

When the judge asked if the lawyer was okay, he took the opportunity to poke fun at his own client, saying as a former boxer he had “taken better shots than him” before sitting back down.

Joseph Zieler was tackled to the floor and removed from the courtroom. Photo / Fox News 4

Zieler sexually assaulted and murdered 11-year-old Robin Cornell and her 32-year-old babysitter Lisa Story in 1990.

Following their murders, the case went cold for more than two decades before new DNA evidence linked Zieler to the crime in 2016.

Already in custody for assaulting his stepson, he was then charged with two counts of murder.

In May, a jury found him guilty and recommended the death penalty.

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

On Monday, Zieler’s fate was revealed by the judge who sentenced him to death following the assault on his lawyer.

The mother of the child Zieler killed was in court and witnessed the attack.