SPOKANE, Wash. -

Spokane Serial Killer Robert Yates is claiming he had ineffective legal counsel in his latest appeal of his death sentence for the killings of two women in Pierce County in the late 1990s.

The appeal, filed in federal court Monday, is asking for the continuance of his stay of execution, appointment of new legal counsel and appeal of his conviction and death sentence for the killing of two women in Piece County on the grounds that he had ineffective counsel at trial.

Yates claims that his defense attorney did not adequately investigate and present evidence that he has a mental disease, investigate Yates' claim that he suffers from brain damage, present evidence at trial of his "many positive relationships, his acts of caring and kindness and the love he feels for his family and they for him" and completely investigate the minimal risk Yates posed of committing future violent acts if his sentence had been life in prison and not the death penalty.

He also claims that his attorney did not present evidence of Yates' cooperation with authorities in Spokane County following his arrest and his decision to plead guilty to provide "a victim's family member with comfort and relief."

The victim in question is Melody Murfin, whose body was found buried in Yates' backyard in a flower bed outside his bedroom window. Yates led authorities to her body as part of his plea deal to be spared the death penalty. As part of that plea agreement Yates confessed to killing 13 women in Spokane County as well as a 1988 murder in Skagit County and a man and a woman in Walla Walla County in 1975, in order to be spared the death sentence.

After he pleaded guilty in Spokane County in exchange for a 408-year sentence, Yates was transferred to Pierce County where then-Pierce County Prosecutor John Ladenburg sought the death penalty against Yates for the killings of Melinda Mercer, whose body was found in Tacoma in December 1997, and Connie LaFontaine Ellis, whose body was found south of Tacoma in October 1998.

At the time of their killings, Yates was a helicopter pilot serving with the Washington Army National Guard, and traveled from Spokane to western Washington to participate in training.

Those murders were prosecuted separately from those in Spokane County, and at trial Ladenburg, who was not party to the plea agreement Yates had agreed to with Spokane County Prosecutor Steve Tucker, brought up the killings he had previously committed outside Pierce County, was found guilty of the killings of Mercer and Ellis and sentenced to death in Oct. 2002.

Previous appeals of his death sentence have been rebuffed. The Washington Supreme Court upheld his death sentence in 2007, the US Supreme Court denied a judicial review request in June 2008, and the Washington Supreme Court rejected a personal restraint petition, filed in September 2008, in March of this year.

The state court also denied his motion to reconsider on May 6, a week before Yates filed his latest appeal.

Yates' stay of execution remains in effect until the court rules on his latest appeal. As the state high court has issued a certificate of finality in the case, if latest appeal is rejected, the state Supreme Court could dissolve his stay at any time.