09/13/2011 09:12 am ET Updated Nov 13, 2011

John Granat, 17, Charged In Murder Of Parents In Palos Park

Updated story

PALOS PARK, Ill. -- A suburban high school student was denied bond Tuesday after being charged in the murders of his parents in Palos Park, about 25 miles southwest of Chicago.

John Granat, 17, called 911 from his home in the 12700 block of 81st Court Sunday morning and told authorities his parents were dead, according to a news release from the Cook County Sheriff's office. The teen told officers he awoke about 7 a.m. and found his home disheveled before discovering his deceased parents.

Upon arrival, officers found John Granat Sr., 44, and Maria Granat, 42, dead in their bedroom. The father died from blunt force trauma to his head and Maria Granat had been stabbed multiple times, the Cook County Medical Examiner's office determined.

According to the sheriff's office, the teen was questioned by officers about his "activities in the hours before he called 911 and late Monday night," and changes in his story along with interviews led to first degree murder charges against him.

The teen told investigators he fell asleep in his basement about 12:30 a.m. and didn't leave the entire night, but his story changed when officers discovered that Palos Heights police stopped Granat for a traffic violation near 122nd Street and Harlem Avenue about 5:17 a.m., the sheriff's office said in a statement.

"He finally told investigators a friend had been in need of money and, while Granat was out of the home, he gave the friend permission to enter," according to a statement from the sheriff's office. He said he fell asleep in his car and entered his home to find his parents dead about 7 a.m.

Several of Granat's friends, however, told officers that the Stagg High School student threatened to kill his parents several times.

Neighbors told the Chicago Tribune the Granat's were "the sweetest, most perfect family" and the sheriff's office had not revealed a possible motive in the slayings early Monday.

John Granat is being held in the Cook County Jail and is due back in court September 20.