By MARK SHERMAN
Associated Press

WASHINGTON - The Supreme Court refused Monday to review a 30-year prison sentence for a teen who was 12 when he killed his grandparents.

Lawyers for Christopher Pittman wanted the justices to examine whether such a long prison term for a child violates the U.S. Constitution's ban on cruel and unusual punishment. With no possibility of parole, he will be 42 before he is released, they said.

Pittman is the only inmate serving such a lengthy sentence for a crime committed at such a young age, his lawyers said. The judge who sentenced him was prohibited by law from taking his age into account.

South Carolina contended that the punishment is proportionate to the crime and said there is a national trend of increased punishment for young violent criminals.

Pittman used a shotgun to shoot Joe and Joy Pittman in their bed and then set fire to their home in 2001. During his trial four years later, Pittman's attorneys unsuccessfully argued that the slayings were influenced by the antidepressant Zoloft - a charge the maker of the drug vigorously denied.

The Supreme Court appeal dealt only with the length of Pittman's sentence.

The South Carolina Supreme Court said Pittman's age belied the complexity of his crime. He planned a double murder, executed an escape plan and concocted a false story of what happened, the state high court said in upholding the punishment.

The state also pointed to recent examples of children as young as 13 receiving sentences of up to life in prison.

Zoloft is the most widely prescribed antidepressant in the United States. In 2004, the Food and Drug Administration ordered Zoloft and other antidepressants to carry "black box" warnings about an increased risk of suicidal behavior in children.

Meg Kinnard contributed to this report.