A juvenile between the ages of 12 and 18 can be tried as an adult if they are charged with any crime that would be a felony if committed by an adult. The court can generally do so without a hearing, however some charges require a hearing before moving to criminal court:
Murder/Homicide
First-degree assault
Rape
Drug trafficking
First-degree robbery
If they have already been adjudicated on two felonies
In 2012, the Missouri State Senate Judiciary Committee passed what's called "Jonathan's Law." The law requires judges to consider giving juveniles convicted as adults a juvenile sentence, and requires an explanation if they do not.
At Combs Law, we believe one of our St. Louis's juvenile crimes lawyers' chief responsibilities is working to ensure your child is not tried as an adult.