Just minutes before he was executed, convicted killer Rodney Berget made a bizarre joke.

On Monday night, Rodney Berget was executed.

The convicted killer was put to death by lethal injection in the US state of South Dakota.

Berget, 56, received the death penalty for killing prison guard Ronald “R.J.” Johnson, during an attempted prison escape on April 21, 2011.

Johnson was beaten with a pipe, while his face was covered with plastic. It was his 63rd birthday.

At the time of the incident, Berget was serving a life sentence for attempted murder and kidnapping.

As The Mirror reports the execution, which was South Dakota’s first since 2012, was delayed for six hours. It was initially scheduled for 1:30pm, but was put on hold while the US Supreme Court deliberated over a last minute legal bid.

Chicago-based attorney, Juliet Yackel, claimed Berget was intellectually disabled and therefore should be legally exempt from punishment.

Just before 6:30pm, the US Supreme Court denied the motion and the execution went ahead.

According to The Independent, when asked whether he had any last words, Berget joked: “Sorry for the delay, I got caught in traffic.”

He then appeared to become emotional. He thanked two specific people for their support throughout his death row sentence.

“I love you, and I’ll meet you out there,” he said while giving the peace sign with his left hand.

At 7:25pm, the drug was administered. The convicted killer groaned and puffed out his chest. Then he drifted off to sleep.

At 7:37pm, he was pronounced dead.

After the execution, Johnson’s daughter, Toni Schafer, spoke about the pain her family has experienced because of Berget’s actions.

“Today was about choices. Berget had choices,” she said, according to USA Today.

“He chose to be evil… to get what he wanted no matter what the cost.

“We choose as a family to be better.”

Witnesses said Berget didn’t apologise to Johnson’s family or even acknowledge what he had done.

Johnson’s widow, Lynette, urged the public not to feel sorry for Berget, explaining he died a much easier death than her husband.

“They broke his neck, they severed fingers, broke his wrists, he didn’t have the back of his head… that’s cruel and unusual punishment,” Johnson said. “What Berget went through… peaceful, clean, sterile, dignified.”