An appeals court was wrong to throw out the conviction and death sentence of a U.S.-British citizen in a 1986 fire that killed an Ohio toddler, the Supreme Court said yesterday in the second death penalty ruling under new Chief Justice John G. Roberts Jr. to go against an inmate.

The unanimous opinion against Kenneth Richey came in a case that had stirred international attention, including a letter from the late Pope John Paul II and a motion signed by 150 members of the British Parliament.

Yesterday's unsigned decision was a sharp rebuke to the U.S. Court of Appeals for the 6th Circuit, which had said that Richey received incompetent legal help in his trial and that prosecutors needed to prove he intended to kill the child.

The justices said the appeals court made mistakes in both of those holdings, relying in part on evidence that may not have been properly filed. The case returns to the appeals court in Cincinnati.

Prosecutors contend that Richey set the blaze to get even with his former girlfriend, who was in the apartment below and had a new boyfriend sleeping over. The fire on June 30, 1986, killed Cynthia Collins, 2.

Richey, who grew up in Scotland, moved to Ohio in the early 1980s to live with his American father. He holds dual U.S. and British citizenship.

A divided panel of the 6th Circuit described sloppy police work and raised questions about whether the fire was even arson. Richey was outside the apartment building in the northwest Ohio town of Columbus Grove and risked his life to save the girl, whose nickname was Scootie, the appeals court said.

A documentary had raised inconsistencies in the case, prompting a campaign for Richey's release. The late pope wrote a letter backing his cause, and 150 members of the British Parliament signed a motion backing Richey's claim of innocence after Prime Minister Tony Blair pledged to look into the case.

Richey's attorney, Kenneth Parsigian in Boston, said his client was frustrated by the prospect of facing another year of appeals. "He's been in jail for 191/2 years for a crime he didn't commit," Parsigian said.