9:15 AM PT -- Margraves has been released from custody and will not be charged with a crime.

The father of 3 of Larry Nassar's victims went nuclear in a Michigan courtroom moments ago -- violently trying to attack the ex-Team USA doctor in front of the judge in his sentencing case.

Moments before the attack, Randall Margraves -- whose 3 gymnast daughters were victimized by Nassar -- asked the judge if she could grant him 5 minutes alone with that "demon" in a locked room.

When the judge denied his request, he tried to negotiate ... asking for one minute.

When the judge shot that request down, Margraves said he wouldn't let the court stop him -- and rushed at Nassar.

Multiple law enforcement officers rushed in and took Margraves down just before he got his hands on Nassar.

As he was being taken into custody, Margraves said, "I want that son of a bitch. Give me one minute with that bastard."