A Texas death row inmate whose attorneys contend is so delusional that he can't understand why he was convicted and condemned has been scheduled for execution.

Scott Panetti, 56, was set for lethal injection in Huntsville on Dec. 3, according to a Gillespie County judge's order received this week by the Texas Department of Criminal Justice, which carries out executions.

Panetti, a native of Hayward, Wisconsin, has a history of mental problems and his case has been to the U.S. Supreme Court at least three times. The most recent was early this month when the justices refused to review his latest appeal. State attorneys have argued he exaggerates some of his symptoms to avoid execution.

Panetti was convicted of fatally shooting his in-laws, Joe and Amanda Alvarado, at their Fredericksburg home 22 years ago in front of his estranged wife and young children. His wife was living with her parents and a week earlier had obtained a court order to keep Panetti away.

His trial judge assigned Panetti a standby attorney after he chose to be his own lawyer at his 1995 trial, where he wore a purple cowboy outfit, flipped a coin to select a juror and wanted to subpoena Jesus Christ and John F. Kennedy as witnesses. He insisted only an insane person could prove insanity.

"Scott Panetti is not competent for execution and therefore his execution would serve no retributive purpose," his appeals attorney, Greg Wiercioch, said Thursday. "It is unfortunate that an execution date has been set.

"He has a fixed delusion that Satan, working through the state of Texas, is seeking to execute him for preaching the Gospel. His execution would be a miserable spectacle."

A day before he was to die in 2007, the Supreme Court stopped Panetti's scheduled execution for further review by lower courts.