Killer of Father and Infant Son - Who Also Tried to Abduct Trial Judge - Is Executed in Texas

A Texas killer who murdered a father and the man's infant son and later attacked his capital murder trial judge has been executed.

James Bigby, 61, showed up at a Fort Worth motel room on Christmas Eve 1987, after prosecutors said he fatally shot Michael Trekell and suffocated Trekell’s 4-month-old son Jayson at their Arlington home.

Read: Day Before Execution, Serial Killer Insists He Didn't Murder 3 Women: 'My Conscience Is Clear'

Years later, as he stood trial on capital murder charges, Bigby reportedly grabbed a loaded gun from behind the presiding judge's bench during a court recess and barged into the judge's chambers.

Officials said Bigby announced, "Let’s go, judge" amid an apparent attempt to abduct him.

The judge and a prosecutor in the case managed to overpower Bigby and pull the gun away. The trial then continued.

Evidence presented by prosecutors showed Bigby killed two other men prior to his 1987 motel room standoff with a SWAT team because he believed they were conspiring with Trekell against him in a worker's compensation suit, The Associated Press reported.

"I regret killing the baby but not the other," Bigby told police.

Police said Bigby confessed to all four murders under questioning but he was never tried in the slayings of Calvin Crane Jr. or Frank Johnson, who were both found shot dead in their homes.

Rejecting an insanity defense in the deaths of Trekell and his son, a jury later sentenced Bigby to die.

Over a decade later, a federal appeals court threw out the sentence in a ruling that said the jury had been improperly instructed during the punishment phase.

Three years after the sentence was overturned, it was reinstated by a jury in Tarrant County.

Watch: Dad Who Lost Daughter in Ohio Execution: The Killer Must Have Known My Family

Bigby was the fourth Texas inmate to be executed this year. Six relatives of his victims watched him die by lethal injection.

"I hope this will bring you peace and I’m sorry for all the pain and suffering," he told them. "I hope that you could forgive me, but if you don’t, I understand. I don’t think I could forgive anyone who would have killed my children."

Watch: Police Search for Killer Who Stabbed Nurse to Death in Her Bedroom