HUNTSVILLE, Texas - Texas prison officials have executed a Fort Worth man condemned for killing a father and his 4-month-old son during a Christmas Eve rampage nearly 30 years ago that also left two other men shot to death.

James Bigby was pronounced dead at 6:31 p.m. Tuesday evening. He was the fourth Texas inmate and the sixth nationally to receive lethal injection this year.

The 61-year-old Bigby was convicted of fatally shooting 26-year-old Michael Trekell and suffocating Trekell's infant son at their suburban Dallas-Fort Worth home. He confessed to the killings but wasn't tried for killing two other men the same day, contending all three men were conspiring against him in his workers' compensation case against a former employer.

At his trial, Bigby grabbed a gun from behind the judge's bench and tried to abduct the judge.