A Chicago area high school student was charged with the brutal murder of his parents in a Cook County, Ill., court Tuesday morning. John Granat, 17, pleaded not guilty to the charges of first-degree murders and was ordered held without bond.

John and Maria Granat, 44 and 42 respectively, were found bludgeoned to death in their bed. The bedroom was splattered with blood from ceiling to floor.

According to prosecutors, the father had his kidney lacerated, jaw broken and teeth knocked out, while the mother had been stabbed repeatedly.

The police said John Granat called 911 on Sunday morning to report the murder of his parents in his Palos Park house. He first told the police that he was sleeping in the basement and when he went upstairs on waking up, he found his parents murdered, authorities said.

But investigators said there were no signs of forced entry. They also found John giving them misleading accounts as he said he fell asleep in the basement and was home the entire night. But Palos Heights police records show he was stopped at 5:17 a.m. for a broken tail light, the Chicago Tribune reported.

Investigators interviewed several of the boy's friends and learned he had previously made multiple threats to kill his parents. John told his friends that he wanted to kill his parents after they learned that he was growing marijuana at their home.

The Tribune quoted sources saying that John's parents threw out the drugs shortly before he threatened to kill them for what they had done.

Granat is being temporarily held at Cermak Hospital at the Cook County Jail, where he is undergoing a full physical and psychiatric evaluation, according to the sheriff's officials.

His next court hearing is set for next Tuesday.