An ex-con sent to Texas' death row for three murders and spared from execution earlier this year by the U.S. Supreme Court is set to take his case before the high court, which may decide whether his attorneys can test items for DNA he claims could prove his innocence.

Hank Skinner was convicted of pummeling his girlfriend with a pickax handle and stabbing her two sons on New Year's Eve in 1993 in their Texas Panhandle home. DNA evidence at his trial showed blood on his clothing from that night was his and from at least two of the victims.

The Supreme Court will hear arguments Wednesday on whether prison inmates may use a federal civil rights law to get DNA testing that was not performed before their conviction. Prosecutors in Skinner's case have refused to make some evidence available for DNA testing, including knives from the scene and a jacket next to one of the bodies.

The arguments come seven months after the Supreme Court spared Skinner just an hour before he was to go to the death chamber. Justices said then they wanted to postpone his execution until they decided whether to review his case.

"The relief Mr. Skinner seeks is simple and limited: the opportunity to obtain access to physical evidence for the purpose of conducting DNA testing," Rob Owen, a University of Texas law professor and Skinner's lead attorney, said in a brief to the high court.

Gray County District Attorney Lynn Switzer has refused to surrender the items and lower courts agreed with her, saying Texas law already gave Skinner "plenty of opportunity" to show additional testing could prove his innocence.

Skinner, a former convicted car thief and parole violator, was trying to "game the system," Switzer said.

Prosecutors have said there's no evidence to conclusively prove Skinner wasn't the killer and that ample evidence exists to show he is guilty. They also contend new DNA testing "would not affirmatively prove anything."

"They're fixing to kill me for something I didn't do," Skinner, 48, said last December from a tiny visiting cage outside death row as his execution date neared.

To head off the scheduled March execution, his legal team renewed its appeals seeking release of evidence for new DNA testing.

Since the Supreme Court justices agreed to look at the case, the high court ruled in a DNA-related case from Alaska that convicts have no constitutional right to test genetic evidence to try to show their innocence. The court said it would not second-guess states or force them routinely to look again at criminal convictions.

Attorneys for Switzer, citing that case, argued in court briefs that Skinner's lawyers hoped to get federal district courts involved in "second-guessing the decisions of state courts" under state DNA statutes. They also noted his trial lawyer chose not to test items Skinner now wants access to, and that using the civil rights law was an improper attempt to circumvent other appeals already refused.

Switzer has the backing of attorneys general from nearly two dozen states, who filed a brief on her behalf.

"He seeks a judge-crafted remedy that he hopes will be more favorable to him," the attorneys general's brief said.

Similarly, the National District Attorneys Association urged the justices to reject Skinner's argument, saying a ruling favorable to him would undermine state law, expand federal jurisdiction over state matters and delay resolution of capital cases.

At his trial in 1995, Skinner's jury heard evidence he was in the house where his girlfriend, Twila Jean Busby, 40, and her two sons, Elwin "Scooter" Caler, 22, and Randy Busby, 20, were killed. Besides the blood on his clothing, Skinner's bloody hand prints were found in the house.

Skinner doesn't deny being in the home at the time of the slayings, but insisted he couldn't have killed them because he was passed out from a mix of vodka and codeine.

Skinner explained that Caler, who had several stab wounds, likely bled on him while trying to roust Skinner from his drunken stupor. And he said he was lying on a couch just a few feet from where Twila Busby was bludgeoned, likely accounting for her blood.

Police were summoned when Caler staggered to the front porch of a neighbor's home. Officers followed a 3½-block-long blood trail to the trailer of a woman Skinner knew. He was found there hiding in a closet.

A defense blood-spatter witness at Skinner's trial acknowledged stains on Skinner's clothing were inconsistent with someone merely laying on a sofa.

Skinner's lawyers want DNA testing on vaginal swabs taken from Busby at the time of her autopsy, fingernail clippings, a knife from the porch of Busby's house and a second knife found in a plastic bag in the house, a towel with the second knife and a jacket next to Busby's body.

Skinner's trial attorney testified at an evidentiary hearing he didn't seek testing of the items Skinner's appeals lawyers now want because he feared the tests would be more damaging to the case.

Skinner and his lawyers point to Twila Busby's now deceased uncle, Robert Donnell, as the possible killer, contending he was a "hot-tempered ex-con" who became more violent when he drank. Donnell and Busby were seen at a New Year's Eve party the evening of the slayings but she returned home early after Donnell's crude remarks and unwanted passes, Skinner's lawyers have said.

Incapacitated from drugs and booze, Skinner didn't go to the party.

Texas has executed 16 inmates so far this year.