OKLAHOMA CITY — The U.S. Supreme Court Tuesday reversed a state appeals court ruling that affirmed the death sentence for an Oklahoma man convicted of first-degree murder in the deaths of a 25-year-old woman and her two children.

The nation’s highest court ruled that a McClain County judge should not have allowed relatives of the victims to tell members of a 12-member jury their opinions on an appropriate sentence for Shaun Michael Bosse, 33. Bosse was convicted and sentenced to death for the July 23, 2010, deaths of Katrina Griffin and her children, 8-year-old Christian and 6-year-old Chastity.

The Oklahoma Court of Criminal Appeals affirmed Bosse’s conviction and death sentence last year. But the Supreme Court said Bosse’s attorney objected when prosecutors asked three of the victims’ relatives to recommend a sentence to the jury. All three recommended death, and the jury agreed.

“…The admission of a victim’s family members’ characterizations and opinions about the crime, the defendant and the appropriate sentence violates the Eighth Amendment” of the U.S. Constitution, which among others things prohibits the imposition of cruel and unusual punishment.

The Supreme Court said the state appellate court ruled that the prohibition on opinions about the sentence by victims’ family members had been “implicitly overruled” in a subsequent decision by the court. But the high court said that prohibition remains intact and that “it is this court’s prerogative alone to overrule one of its precedents.”

The decision remands the case back to the state appeals court for further review. The ruling does not affect Bosse’s conviction on three counts of first-degree murder.

District Attorney Greg Mashburn, who prosecuted the case, said he hopes the state appellate court will rule that the admission of the victims’ family members’ opinion about an appropriate sentence for Bosse was “harmless error” and reinstate his death penalty.

“My hope is that the Court of Criminal Appeals will look at that in the totality of the circumstances,” Mashburn said.

The Office of the Chief Medical Examiner ruled that Katrina Griffin died from multiple sharp force trauma, while Christian died from multiple stab wounds. The report says Chastity died from smoke inhalation and burns after the family’s mobile home in Dibble was set on fire.

Authorities say Chastity had been thrown into a closet and a chair was used to block the door. Evidence inside the home linked Bosse to the deaths, according to authorities.

Prosecutors said Bosse, Katrina Griffin’s boyfriend, had the victims’ blood on his clothing and that scratches were on his knuckles and arm. Authorities also found pawn tickets in his wallet indicating he hocked some of the nearly 140 items taken from the family’s home.