At precisely 4 p.m. yesterday, a buzzer sounded at the Anne Arundel County Detention Center. A black door swung open and, under gathering clouds, out walked Leeander J. Blake, a clear plastic bag over his right shoulder, his left hand buried in a pants pocket.

Blake said nothing, his gaze fixed forward as he and a lawyer threaded past a waiting media throng. He climbed into the passenger seat of a black Ford Explorer and then, 20 months after he and an associate were accused of a brutal carjack killing in downtown Annapolis, drove away as a free man.

Police and prosecutors say they believe Blake, 18, got away with murder.

Last month, the state Court of Appeals ordered that Blake be freed. The court said a provision in state law -- that prosecutors who appeal pretrial rulings must drop charges if they lose -- compelled his release. Unless the state appeals to the U.S. Supreme Court, an action that is said to be likely, Blake cannot be charged again in the slaying.

Kristin Riggin, a spokeswoman for the Anne Arundel County state's attorney, called Blake's release "a bitter pill to swallow." When the court issued its ruling, State's Attorney Frank R. Weathersbee used stronger language, saying of Blake: "He can say, 'I got away with murder.' "

Blake's attorney, Kenneth Ravenell, said yesterday that there is no evidence that his client committed murder. He said Blake has admitted that he was present during the killing and has named another man, Terrence Tolbert, as the gunman and driver.

Ravenell acknowledged that "no one in the citizenry is happy that Leeander Blake has been released" but said the court's proper application of the law represents a larger victory.

Straughan Lee Griffin was killed outside his home in the city's historic district Sept. 19, 2002. Griffin, 51, who lived one block from the governor's mansion and not far from the U.S. Naval Academy, was unloading groceries when two men approached and shot him in the head. As the assailants fled in Griffin's Jeep Cherokee, they drove over his body. The crime stunned the city. No one had been slain in the historic district since the 1960s.

More than a month later, police arrested Blake and Tolbert, then 19, who were neighbors in an Annapolis public housing complex. The appellate ruling on Blake does not affect the case against Tolbert. His case is scheduled to go to trial Sept. 21.

Court documents say Blake, then 17, was arrested in the early morning and taken to Annapolis police headquarters. Blake told the lead detective, William Johns, that he would not speak without a lawyer present. Before a lawyer arrived, Johns returned to Blake's holding cell and presented him with a statement of the charges against him.

The papers said Blake faced the death penalty, court documents show, though he was actually too young to be considered for capital punishment. As Blake held the papers, an officer made a remark that eventually undid the prosecution's case. "I bet you want to talk now, huh?" Officer Curtis Reese said.

Soon afterward, Blake asked to talk with detectives. He made a statement in which he acknowledged being at the scene of the crime but said Tolbert shot Griffin, according to Blake's attorney and an Annapolis police spokesman. Blake's attorney asked to have the statement suppressed, saying Reese's remark constituted an interrogation, which is prohibited after a suspect has asserted his right to an attorney. An Anne Arundel Circuit Court judge agreed with Blake.

Weathersbee faced a difficult choice: go to trial without the statement and risk losing the case, or appeal and risk having to drop the case. He chose the latter, largely because the remaining evidence was, by his own account, "skimpy."

The Court of Appeals sided with the defense, ruling that Reese's remark had tainted the statements Blake made later.

The state has 90 days from June 16, when the Court of Appeals rejected a request that it reconsider, to appeal. In the meantime, prosecutors have decided not to drop the case.

"We're almost certain to appeal to the Supreme Court," said Kevin J. Enright, a spokesman for Maryland Attorney General J. Joseph Curran Jr.