WASHINGTON - The Supreme Court split 5-4 in a death row case yesterday, ruling against a convicted killer who wanted a second chance because his lawyer didn't disclose that he previously represented the victim.

The court said Walter Mickens Jr. received effective counsel even though he did not know his lawyer once represented the troubled 17-year-old boy Mickens was accused of sexually assaulting and killing.

Dissenting justices said Mickens was victimized himself by the justice system.

"A rule that allows the state to foist a murder victim's lawyer onto his accused is not only capricious; it poisons the integrity of our adversary system of justice," Justice John Paul Stevens wrote. "Mickens had a constitutional right to the services of an attorney devoted solely to his interests."

Mickens had been convicted and sentenced to death in the 1992 killing and sexual assault of Timothy Hall. Hall was stabbed 143 times in Newport News, Va.

Mickens, like many poor criminal defendants, had been appointed an attorney to defend him. The lawyer also was chosen months earlier to represent Hall in an unrelated case.

The court is reviewing two other death-row cases with constitutional questions. They will decide whether states can execute the mentally retarded and if it is constitutional for a judge, not a jury, to decide a death sentence.

Justice Antonin Scalia, writing the opinion in yesterday's case, said the judge in Mickens' trial was not at fault for not uncovering a potential conflict. He also said the conflict alone did not justify throwing out Mickens' death sentence.

Mickens' new lawyers had claimed a violation of the Constitution's Sixth Amendment, which guarantees the right to a lawyer.

The lawyer, Bryan Saunders, did not tell the jury that Hall may have been a willing sexual partner for Mickens, the new lawyers said, which could have changed the penalty.

When the jury was deciding if the crime merited a death sentence, Saunders did not challenge Hall's mother when she made an emotional statement about her son on the stand. Saunders knew that all was not well between mother and son - he had represented Hall in an assault case brought by Hall's mother.

The 4th U.S. Circuit Court of Appeals had ruled against Mickens. The Supreme Court affirmed that decision. Joining Scalia were Chief Justice William H. Rehnquist and Justices Sandra Day O'Connor, Anthony M. Kennedy and Clarence Thomas.

The case is Mickens v. Taylor, 00-9285.