WASHINGTON -- The Supreme Court ruled yesterday that Arizona school officials violated the constitutional rights of a 13-year-old girl when they subjected her to a strip search on the suspicion that she might be hiding ibuprofen in her underwear.

The court ruled 8-1 that such an intrusive search without the threat of a clear danger to other students violated the Constitution's protections against unreasonable search or seizure.

Justice David Souter, writing perhaps his final opinion for the court before retirement, said that in the search of Savana Redding, now a 19-year-old college student, school officials overreacted to vague accusations that she was violating school policy by possessing the ibuprofen, equivalent to two Advils.

What was missing, Justice Souter wrote, "was any indication of danger to the students from the power of the drugs or their quantity, and any reason to suppose that Savana was carrying pills in her underwear."

Justice Clarence Thomas raised the lone dissent. "Judges are not qualified to second-guess the best manner for maintaining quiet and order in the school environment," he wrote.

In what was the court's next to last day in issuing decisions from the 2008-2009 term, the justices also:

• Ruled 5-4 that forensic reports prepared for criminal trials are the same as testimony for the prosecution, and that those who prepare them must be available for cross-examination by defense lawyers. The dissenters said such a requirement was a dramatic change in criminal proceedings and could have a debilitating impact on the criminal justice system.

• Criticized a federal court's supervision of the way Arizona provides language instruction to its non-English speaking student, and raised questions about whether the federal court had overstepped boundaries in dictating how states provide services. The court's liberal dissenters said the 5-4 decision "risks denying school-children the English-learning instruction necessary to overcome the language barriers that impede their equal participation."

The strip-search case was one of the most dramatic of the term for the court, prompting an intense oral argument and leading to charges from Justice Ruth Bader Ginsburg that her all-male colleagues had failed to appreciate the trauma that such a strip search would have on a developing teenaged girl.

Safford Middle School Vice Principal Kerry Wilson had pulled Savana Redding out of class after another student was found with prescription-strength ibuprofen, and said she had gotten them from Ms. Redding.

Mr. Wilson took her to his office, and a search of backpack and outer clothes turned up no contraband. He then had a school nurse take Ms. Redding to her office, where she was made to remove her clothes, shake out her bra and pull her underwear away from her body, "thus exposing her breasts and pelvic area to some degree," Justice Souter wrote.

Nothing was found, and the former honors student said she was so humiliated by the incident that she never returned to the school. Her mother filed suit against the school district, as well as Mr. Wilson.

After years of legal proceedings, the full 9th U.S. Circuit Court of Appeals eventually ruled in her favor.

The divisions apparent during the court's oral arguments on the case largely disappeared in the opinion that said the search was unreasonable. Justices based their view on the court's warning in a 1985 case that, while school officials have leeway in deciding when searches of students are reasonable, the officials may not employ searches "excessively intrusive in light of the age and sex of the student and the nature of the infraction."

Lower courts have had trouble deciding when that standard applies, Justice Souter wrote, so Mr. Wilson should not be held personally liable for the incident. The court ruled, though, that Ms. Redding's suit could proceed against the school district.

Justices Ginsburg and John Paul Stevens criticized the decision to remove Mr. Wilson from the suit, saying he should have known that the search violated Ms. Redding's rights. "Abuse of authority of that order should not be shielded by official immunity," Justice Ginsburg wrote.