The Supreme Court declined to impose new restraints on police questioning of juveniles yesterday, ruling that a California state court had reasonably upheld the murder conviction of a 17-year-old who confessed to a detective without being advised of his rights to remain silent and to have an attorney present.

By a vote of 5 to 4, the justices ruled that under applicable Supreme Court precedents, the California Court of Appeal did not have to factor in the youth and inexperience of the suspect, Michael Alvarado, when it decided that he was not clearly in custody during his two-hour session with a detective. The requirement that police advise interviewees of their rights applies only to those who are under arrest or who, under the circumstances, reasonably believe they are not free to leave.

"Our opinions applying the Miranda custody test have not mentioned the suspect's age, much less mandated its consideration," Justice Anthony M. Kennedy wrote for the majority, referring to the 1966 Supreme Court case that first required authorities to inform suspects of their rights once they are in custody.

Kennedy acknowledged that "fair-minded jurists could disagree over whether Alvarado was in custody" -- but said that was a reason to uphold the conviction because federal law requires federal courts to accept constitutional decisions by state courts unless they are clearly unreasonable or violate Supreme Court precedent.

The case had attracted attention as a test of the court's views on juvenile interrogation, especially after such recent cases as that of five New York teenagers who served prison sentences for the 1989 beating and rape of the woman who became known as the Central Park jogger based on confessions that they later recanted and that new DNA evidence proved false.

In a friend-of-the-court brief supporting Alvarado, the National Association of Criminal Defense Lawyers urged the court to take into account "the special vulnerabilities attendant to youth," which the organization argued have led to police "abuse" in questioning juveniles.

For its part, the Bush administration, supporting California's state authorities, told the court in a friend-of-the-court brief that "age and experience are not relevant considerations in determining whether a juvenile is 'in custody' under Miranda."

But yesterday's decision, while rejecting new limits on police questioning based on suspects' age, does not rule out the possibility that age-based limitations could be taken into account in a future case.

Justice Sandra Day O'Connor, who provided a fifth vote to a majority that also included Chief Justice William H. Rehnquist and Justices Antonin Scalia and Clarence Thomas, added a short concurring opinion in which she qualified her vote by noting that, although Alvarado was nearly 18, "there may be cases in which a suspect's age will be relevant to the Miranda 'custody' inquiry."

In dissent, Justice Stephen G. Breyer, joined by Justices John Paul Stevens, David H. Souter and Ruth Bader Ginsburg, said that "[c]ommon sense, and an understanding of the law's basic purpose in this area, are enough to make clear that Alvarado's age . . . is also relevant to the inquiry."

"What reasonable person in the circumstances . . . could have thought to himself, 'Well, anytime I want to leave I can just get up and walk out?' " Breyer wrote.

The case began on Sept. 17, 1995, when Alvarado and another man tried to hijack a truck in Santa Fe Springs, Calif. The other man shot the driver to death.

A month later, police asked Alvarado's mother to bring him in for an interview. Alvarado appeared at the station accompanied by both parents.

His parents asked to come with him to an interrogation room but were kept outside as he spent two hours talking with a detective, who did not place him under arrest but eventually elicited an admission that he had been involved in the crime. Then, Alvarado went home.

A month after that, police issued a warrant for Alvarado's arrest, and he turned himself in. He was convicted of second-degree murder based on his confession and sentenced to 15 years to life.

The case is Yarborough v. Alvarado, No. 02-1684.