A Navy retiree who was 16 years old when he fatally stabbed and robbed a clerk at a Merrifield 7-Eleven in 1975 was convicted of murder yesterday and sentenced to a 25-year prison term eight months after his conscience told him to turn himself in.

Paul S. Sorensen, 44, told a Fairfax County Circuit Court judge that his teenage crime weighed heavily on him as he went about his daily life for more than 25 years, pursuing a successful naval career and raising children. Sorensen said he believed that God allowed him to recover from cancer so he could be punished for the Jan. 19, 1975, slaying of Jesse Thomas Shriner.

"I am here to stand before you and take my justice," Sorensen said. "I want to . . . atone for what I have done."

During a hearing yesterday, Sorensen entered Alford pleas to charges of first-degree murder and robbery. Under an Alford plea, a defendant does not admit guilt but acknowledges there is enough evidence for a judge or jury to convict.

Fairfax County Commonwealth's Attorney Robert F. Horan Jr. said Shriner, 46, was stabbed several times. Both cash registers had been opened, and only some change remained in them, he said.

Sorensen, who was a junior at Oakton High School and lived near the convenience store, became a suspect early in the investigation when detectives found a shoe print they believed was his, Horan said. But he said investigators didn't find enough evidence to file charges, and the case went unsolved for years.

At some point, Horan said, Sorensen's ex-wife went to the Naval Criminal Investigative Service and told officials that Sorensen confessed to her that he had killed someone when he was a teenager. In April, Horan said, Sorensen repeated that confession to Fairfax detectives who had traveled to Sorensen's home in Corpus Christi, Tex.

Sorensen took a train from Texas to Virginia in May and turned himself in to police.

Melanie Landis, Shriner's niece, traveled from York, Pa., yesterday so she could see Sorensen in court. Landis was 11 when she picked up the phone and listened in as her grandmother, Shriner's mother, learned of her son's death.

"My grandmother died two years ago not knowing it would come together," Landis said. "Someone from the family had to be here. It's taken a long time, but it's finally been closed."