( CNN ) -- A 17-year-old accused in a high school shooting that left three dead in Ohio pleaded not guilty Friday , and his bail was set at $ 1 million . T.J. Lane was indicted in the shooting deaths of three classmates at Chardon High School . A judge ruled last month that he could be tried as an adult . Lane sat quietly during Friday 's brief proceedings , answering a few questions from Geauga County Judge Forrest Burt . Lane 's attorneys said they reserved the right to enter a later plea of not guilty by reason of insanity . Authorities allege that on February 27 , Lane walked up to a table at the high school cafeteria and started firing . `` He was silent the entire time , '' said Nate Mueller , who was a few feet away from the gunman . `` There was no warning or anything . He just opened fire . '' A teacher identified as Frank Hall helped chase the gunman out of the school . Police arrested Lane a short time later . When the violence ended , six students had been shot , and in the following days , three died : Daniel Parmertor , 16 ; Demetrius Hewlin , 16 ; and Russell King Jr. , 17 . Finding 'new normal ' after school shooting . Days after the attack , prosecutor David Joyce said Lane admitted taking a .22-caliber gun and a knife into school that morning and firing 10 rounds , choosing his victims randomly . Joyce said that in the months since the bloodshed , he has met with the families of the victims on a constant basis . `` Their child was murdered , '' he said . `` Justice for them would be to see Mr. Lane detained for an extended period of time . '' Though Lane could be tried as an adult , federal law prohibits capital punishment for anyone under the age of 18 . `` Obviously , he ca n't be put to death as a juvenile , but he can certainly be sentenced to life without parole , '' Joyce said . `` That 's up to a jury to decide . '' Lane was indicted on six charges : three counts of aggravated murder , two counts of attempted aggravated murder and felonious assault . Burt ordered Lane to a juvenile detention center until June 18 , when he will be transferred to the Geauga County Jail .
NEW : Attorneys say they might enter plea of not guilty by reason of insanity . T.J. Lane , 17 , is accused of fatally shooting three high school classmates in February . He has pleaded not guilty to the charges and faces life without parole if convicted at trial. A judge ruled in May that he can be tried as an adult .