A federal judge on Monday declined to halt the execution of former Sweetwater cop and mass killer Manuel Pardo, who is slated to be executed Tuesday.

Prosecutors said Pardo, 56, and cohort Rolando Garcia committed nine murders during the 1980s, ripping off drug dealers and people who could implicate them in the crimes. At a 1988 trial, he admitted the murders, saying he was ridding the streets of the “scum of the earth.”

At trial, lawyers for Pardo — a former highway patrolman, Boy Scout leader and decorated Navy veteran — argued he was insane at the time of the crimes.

After Gov. Rick Scott signed his death warrant in October, Pardo’s lawyers asked Miami-Dade Circuit Judge Stanford Blake to stay the execution, saying Pardo had not been given all the public records associated with his case and that back in the 1980s he was incompetent to stand trial.

Pardo’s lawyers also said state’s method of lethal injection was “cruel and unusual” punishment. Blake denied the appeals. The Florida Supreme Court also upheld Blake’s decision.

In an order Monday, U.S. Judge Timothy Corrigan said the claims were filed too late and that the state’s method of execution, which includes the injection of three drugs, has already been examined by the Florida Supreme Court and a federal appeals court.

Pardo is slated to be executed Tuesday at 6 p.m. at the Florida State Prison in Starke.

The convicted killer is still appealing to the U.S. Supreme Court, and is also likely to appeal to the U.S. 11th Circuit Court of Appeals in Atlanta.