MIAMI - The US state of Florida on Wednesday executed a man known as “the ninja killer”, more than three decades after a split jury handed him a death sentence for the murder of a couple in 1989.

Louis Gaskin, 56, was put to death by lethal injection at 6.15pm (6.15am on Thursday, Singapore time), the Florida Department of Corrections said in a statement.

Gaskin’s sentence is one of three executions approved so far in 2023 by the state’s Republican Governor Ron DeSantis.

Gaskin earned his nickname from the media because he wore all black during a deadly burglary on Dec 20, 1989.

Armed with a rifle, he fired through the window of a New Jersey couple’s winter home, killing a man and wounding his wife, according to court documents. He eventually fatally shot the woman as she attempted to flee.

The clock, lamps and other objects he stole from the house were to be Christmas gifts for his girlfriend.

Gaskin robbed a second house later that night, injuring a man who then, along with his wife, fled in his car.

Gaskin confessed to the crimes when he was arrested about two weeks later, and was found guilty of the two murders.

The jury voted eight to four to recommend the death penalty.

At the time, only a majority vote was required for capital punishment.

The state now requires a unanimous vote to recommend execution.

In the decades since Gaskin’s conviction, his lawyers have lodged multiple appeals, arguing he suffered from psychological disorders.

In 1991, a Florida appeals court recognised that he suffered from schizophrenia and auditory hallucinations, but judged that he remained conscious of the gravity of his actions and thereby was legally responsible.

Mr DeSantis signed off on Gaskin’s execution orders in March, and the United States Supreme Court rejected his final appeal.

The governor, considered to be a potential 2024 Republican presidential contender, oversaw only two executions during his first term.

But since January, with speculation about a presidential run heating up, he has signed off on three execution orders.

Ms Noreen Rector, who escaped from Gaskin’s second robbery, said she opposed the execution.

“I would be satisfied if Louis remained in prison, without the possibility of release. I don’t believe the death penalty serves any purpose,” Ms Rector wrote in a statement to The Daytona Beach News-Journal, a local Florida paper.

“What will really bother me,” she said, “is if this might, in some way, advance Florida Governor DeSantis in his presidential quest.”

The death penalty is legal in 27 US states, though three have imposed a moratorium on the practice – as has the federal government under US President Joe Biden.

Since the beginning of 2023, 10 people – including Gaskin – have been put to death: five in Texas, two in Missouri, two in Florida and one in Oklahoma. AFP