ONEIDA — State police on Thursday arrested a 13-year-old boy in the shotgun slaying of his father.

Joseph Giacona III was indicted Thursday on a second-degree murder charge in the death of his 37-year-old father, Joseph Giacona Jr. He was arraigned in Oneida County Court and was due back in court Oct. 3 with an attorney. State police said he would be prosecuted as an adult.

The teen has denied any involvement in his father’s death, state police officials said at a news conference.

His mother, Rachelle Rustici, said she stands by her son’s innocence “100 percent.”

“I just hope that it takes a very short time for them to find out that he is not the one who did it,” Rustici said. “I can’t believe that, with everybody working on the case, they couldn’t find another direction to go down.”

The elder Giacona was found dead in his Vernon home Jan. 24.

State police previously have said that Giacona III reported his father’s fatal gunshot wound shortly after returning home from school that Thursday afternoon. Giacona lived with his two sons and his fiancDee, Michelle Lubeck.

During the eight-month investigation, state police released very few details regarding the circumstances surrounding the death. On Thursday, they declined to discuss any possible motive for the shooting.

AP-ES-09-25-08 1615EDT