– Defense attorneys for a 17-year-old accused of plotting a Columbine-style massacre at the local junior and senior high school entered the equivalent of a not-guilty plea Monday in a juvenile court proceeding.

John David LaDue, thin and with a short haircut, wore a bright orange jail jumpsuit as he sat between two public defenders and calmly answered a judge's procedural questions.

LaDue is accused of plotting to kill his family and then going to the school with pressure cooker bombs, firearms and ammunition, setting off explosions in the cafeteria, shooting the school liaison officer and killing students.

Authorities say a 180-page notebook, which dates back to July, outlined his plans.

He was arrested April 29 after a citizen called police when she saw him suspiciously enter a storage locker.

Prosecutors are seeking to have LaDue certified as an adult in the case, a court process that could take a couple of months. It will involve experts reviewing school and other records as well as psychological exams of the teen. Defense attorneys may have a similar study ­conducted.

LaDue was charged as a ­juvenile with four counts of attempted murder, two counts of first-degree damage to property and six counts of possession of a bomb by someone under 18. If convicted of one count of first-degree attempted murder as an adult, LaDue could serve up to 18 years, according to state guidelines. But if he's convicted as a juvenile, he could be released from detention when he turns 21.

The state had asked that LaDue be moved from the Red Wing juvenile facility where he is being housed to one in Lino Lakes so he would be closer to a state psychological ­evaluator.

Judge Gerald Wolf denied that request for now. Red Wing allows easier access for LaDue's parents to visit their son, defense attorneys argued.

After the hearing, defense attorney Dawn Johnson said that she believes LaDue is holding up well "for someone who's never been in trouble like this before."

The teen is "a very intelligent young man" and able to communicate well with his lawyers, she said. He is in a room by himself in the Red Wing facility, she said, as one of only a couple of teens there on pretrial ­status.

Upon entering the courtroom, LaDue stared at his father, who was sitting in the gallery wearing a black long-sleeved National Rifle Association T-shirt that read "Don't tread on me."

The judge scheduled LaDue's next hearing for June 18. Defense attorneys will argue then that prosecutors don't have probable cause for the charges against the teen.

Outside the courtroom, Johnson added: "Particularly for the attempted murder charges, there has to be an act in furtherance of one's intent, and we don't believe that the state can establish that."

LaDue had a right to such a hearing within 14 days but defense attorneys wanted to schedule it for later after receiving volumes of police reports last week, Johnson said.

In court, the judge asked LaDue whether he understood the delay, and LaDue said yes.

"I authorize them to extend it beyond 14 days," LaDue calmly told the judge.

LaDue arrived to court in shackles. The judge ordered that he will be able to wear street clothes to his next hearing, granting a request from his defense attorneys.