Maryland's efforts to prosecute a man who admitted involvement in one of the most publicized slayings in Annapolis in recent memory effectively ended yesterday as the U.S. Supreme Court let stand a ruling that an incriminating statement he gave police was taken improperly.

The court's decision to dismiss the case means that, unless federal authorities bring charges, Leeander J. Blake will never face trial in the first slaying in the city's historic district since the 1960s.

Blake, under questioning by police in October 2002, admitted that he was present when local businessman Straughan Lee Griffin, 51, was killed Sept. 19 while unloading groceries outside his home, police and prosecutors say.

"As far as state law is concerned, he can say he got away with murder," Frank R. Weathersbee, state's attorney for Anne Arundel County, said yesterday.

The case against Blake, 20, began to unravel in June 2003 when a trial court threw out his statement, ruling that police violated his rights by effectively interrogating him after he had asked for a lawyer. Prosecutors appealed that ruling and lost. Under the law in place at the time, they were then required to drop the charges.

In April, the U.S. Supreme Court agreed to hear the case, leading some legal experts to conclude that the court was poised to provide new guidelines for the treatment of suspects who invoke their right to counsel, potentially altering how police across the country conduct interrogations.

But yesterday, less than two weeks after it was argued, the court dismissed the case without resolving the issue either way. The one-sentence order means only that, for reasons that were not explained, a majority believed the court's intervention was not appropriate, said Abraham Dash, a law professor at the University of Maryland who has followed the case.

In October 2002, Blake's interrogation was brought to a halt when he asked to see a lawyer. A short time later, he was notified in a charging document that he could be executed. A police officer then remarked, "I bet you want to talk now, huh?"

A half-hour later, Blake did talk, telling Detective William Johns that he was at the crime scene but was not the gunman.

At the Supreme Court, both sides agreed that the officer's remark violated Blake's rights. The state, however, argued that Johns had effectively remedied the damage by remarking within earshot of Blake: "No, he doesn't want to talk to us. He already asked for a lawyer. We cannot talk to him now." The state argued that Blake then freely decided to speak.

Kenneth W. Ravenell, Blake's attorney, argued that Johns's remedy was insufficient, noting that a lower court had found that the officer's remark was intended to provoke a response. Ravenell contended that allowing police to use statements obtained as a result of violations of suspects' rights would only lead to deliberate violations.

Yesterday, Ravenell said of Blake: "He is, to say the least, ecstatic that this case maybe has finally come to an end for him and he can move on to doing some productive things in his life."

Maryland U.S. Attorney Rod J. Rosenstein said his office would evaluate the case to determine whether federal prosecution would be appropriate. Griffin's assailants took his car, and carjacking is a federal crime.

It is not yet clear whether the statement Blake gave might be admissible in a federal prosecution. The state court rulings are not binding on federal courts and, in dismissing the case yesterday, the Supreme Court did not rule either way.

An acquaintance of Blake's, Terrence Tolbert, was convicted in January and sentenced to life in prison without the possibility of parole for his role in the slaying. The case against Tolbert relied largely on two police officers' testimony that Tolbert incriminated himself during interviews. At trial, Tolbert admitted being present during the slaying but contended that Blake fired the shot that killed Griffin.

"All of us in the family are obviously very disappointed," said Linda Griffin, who has said it would be "horrific" if Blake were not brought to trial for her brother's murder. "It did not even occur to me that this was a possibility. None of us were expecting this."