LIHU'E, Kaua'i — Richard Costa, 37, was found guilty this week of second-degree murder in the Jan. 13, 2005, stabbing death of 18-year-old Weslyn Jerves of Hanama'ulu.

Jerves' body was found alongside an old cemetery near Glass Beach in Port Allen. She had been stabbed and there were tire tracks on her body.

Prosecutors Craig De Costa and Jennifer Winn used DNA evidence to prove Jerves had been in Costa's vehicle. Costa, of Kalaheo, admitted Jerves had been a passenger in his car, that they fought and that he stabbed her. After leaving her at the scene of the slaying, near an area called Glass Beach at Port Allen, Costa said he felt a bump as his car left the area. Investigators found the tracks on Jerves' body matched the tires on Costa's car.

Defense attorney Warren Perry argued self defense, and suggested Costa was impaired by severe depression and not responsible for his actions, but state expert witnesses said he was able to tell right from wrong and could control his actions.

Sentencing is May 25.