CHARDON, Ohio (CBS/AP) -- Prosecutors have until Thursday to bring charges against TJ Lane, the suspect in the Chardon High School shooting rampage. They are also expected to ask that he be tried as an adult.

CNN reports Ohio attorney general Mike DeWine said, "I have not talked to the prosecuting attorney, David Joyce, yet, but what we would assume is this case...[Lane] would be tried in all likelihood as an adult."

At a news conference shortly after Lane's initial hearing Tuesday, David Joyce said the fatal shootings Monday were not about bullying or drugs. The prosecutor says defendant TJ Lane is "someone who's not well." However, Joyce did not provide a motive for the attack.

Prosecutors told ABC News that the 17-year-old now stands accused of murdering the three students that he "chose randomly."

"[Lane] confessed to taking the pistol and admitted he went into the cafeteria and shot 10 rounds," Joyce said. "[He said he] did not know the students but chose them randomly."

In court, Lane appeared shy, saying only "yes, sir" in answer to a judge's questions as his eyes darted back to the floor.

Lane's grandfather and two aunts sat beside him in court. Joyce asked that Lane be kept in detention and his attorney did not object, so the judge ordered Lane to be taken to a detention facility.

"TJ Lane will remain in detention during proceedings due to serious nature of allegations and charges," Judge Timothy Grendell said.