Updated

A man convicted of murdering four children with an assault rifle was executed Wednesday, becoming the first Tennessee inmate put to death by electrocution since 1960.

Daryl Holton, 45, had confessed to shooting his three young sons and their half-sister in 1997 in the town of Shelbyville, about 50 miles south of Nashville.

Holton told police he killed the children because his ex-wife had refused to let him see them. He said he intended to kill her and himself, but instead turned himself in.

As the hours ticked away Tuesday night, a group of attorneys petitioned the state Supreme Court to stop the electrocution, saying the execution method was cruel and unusual punishment. But the court rejected the petition.

Holton chose the electric chair over the state's preferred execution method of lethal injection. Under Tennessee law, death row inmates can choose, if their crimes were committed before 1999.

Holton, a Gulf War veteran, confessed to the 1997 killings, saying he lined up the children at his uncle's auto repair garage and shot them.

Holton has said he suffered from severe depression when he committed the murders. His lawyers maintain he has a long history of mental illness and may suffer from post traumatic stress disorder from his military service in the 1991 Gulf War.

Holton's spiritual adviser, Dixie Gamble, had been visiting him daily and said he was at peace.

He came within a day of execution a year ago before a federal appeals court issued a stay. He was among four death row inmates whose executions were postponed in February, when Gov. Phil Bredesen placed a 90-day death penalty moratorium.

Bredesen had cited a number of problems with the state's execution guidelines, including a jumble of conflicting instructions that mixed lethal injection instructions with those for the electric chair.

The Correction Department completed the revision of its procedures in March, the moratorium was allowed to expire and the four executions were rescheduled.

The last inmate executed by electric chair was convicted rapist William Tines on Nov. 7, 1960.