The State has discretion In cases where there is an option to charge a person as a juvenile or as an adult. This discretion is based on Arizona statutes and case law. The more serious the offense, the more likely the State will be inclined to charge as an adult. In some cases, the State can charge minors as young as 14 or 15 years old as an adult.
There are many murder cases where juveniles can be tried as an adult. For instance, if a person is 17 years old, the State is allowed to charge them as an adult if it is a serious enough offense. If a person under 18 years of age, for instance your son or daughter, you should contact an attorney immediately.