Attorneys for a condemned Missouri man and several former judges on Monday asked the U.S. Supreme Court to halt his upcoming execution, saying a mistake by his former lawyers cost him the chance to appeal his case through the federal courts.

The state of Missouri is scheduled to execute Mark Christeson at 12:01 a.m. Wednesday for killing a southern Missouri woman and her two children in 1998. He would be the ninth person put to death in Missouri this year.

Christeson's attorneys and 15 former judges filed a brief Friday with the 8th U.S. Circuit Court of Appeals claiming Christeson was denied federal court review because court-appointed attorneys missed the deadline to file a federal appeals petition by four months.

The 8th Circuit refused the request, prompting the appeal to the Supreme Court.

Sarah Turberville, an attorney for The Constitution Project, a Washington-based organization working with the former judges, said it is rare for anyone to face execution without having appealed the case in federal court.

She said Christeson's court-appointed attorneys, who took over his case in July 2004, had until April 2005 to file the petition seeking federal court review. The petition was filed 117 days late, and a U.S. District Court in Missouri refused to hear the case, Turberville said.

"Not having federal court review means there's been no independent examination regarding the fairness of the trial and the appropriateness of the death sentence," Turberville said. "No federal court has been able to address these issues at all."

The judges behind the friend-of-the-court brief are former state appellate and federal judges who had no role in the case, Turberville said.

Several Missouri religious leaders have asked Gov. Jay Nixon to grant clemency and stop the execution, citing concerns about the missed deadline and that Christeson isn't mentally competent to be executed. Scott Holste, a spokesman for Nixon, said the governor is still reviewing the case.

Nanci Gonder, a spokeswoman for Missouri Attorney General Chris Koster, declined to comment.

In 1998, Christeson, then 18 years old, and his cousin, Jessie Carter, 17, were living with a relative about a half-mile from where Susan Brouk lived with her 12-year-old daughter, Adrian, and 9-year-old son Kyle.

On Feb. 1, the cousins broke into the Brouk home and used shoelaces to tie up the kids. Christeson raped Brouk in a bedroom. When they went back into the living room, Adrian said Carter's name.

Knowing they were identified, Christeson said, "We've got to get rid of 'em."

The cousins took the family to a nearby pond. Brouk and Kyle were stabbed and thrown into the pond to drown. Adrian suffocated when Christeson pressed on her throat while Carter held her.

Christeson and Carter were captured Feb. 9 in California. Both were convicted of three counts of first-degree murder. Carter was sentenced to life in prison without parole.

The Associated Press