A federal judge has denied a request by condemned killer Ron Lafferty to halt his federal case so he can pursue a number of legal claims in state court.

Attorneys for Lafferty filed an amended petition in July. Lafferty, 75, says the state mishandled or destroyed parts of a bloodied kitchen drape that was used as evidence in the case, and that Utah's methods of execution — firing squad and lethal injection — violate Eighth Amendment protections against cruel and unusual punishment.

But U.S. District Judge Dee Benson denied the petition Friday.

Lafferty is on Utah's death row after a 1985 conviction for the murders of his sister-in-law Brenda Wright Lafferty and her 15-month-old daughter, Erica, in Utah County.

The 10th Circuit Court of Appeals later overturned the conviction and ordered a new trial after finding that the wrong standards had been used to evaluate Lafferty's mental competency. Lafferty was convicted and sentenced to death again for the murders in 1996.

According to trial testimony, Lafferty ordered the slayings after receiving a revelation from God. His brother Dan Lafferty carried out the 1984 murder by slashing their victims' throats with a 10-inch boning knife at their home in American Fork. Dan Lafferty also was convicted of murder, but he is serving a life sentence without the possibility of parole.

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