Maryland Code, Courts and Judicial Proceedings § 3-8A-16

(a) The official in charge of a jail or other facility for the detention of adult offenders or persons charged with crime shall inform the court or the intake officer immediately when a person, who is or appears to be under the age of 18 years, is received at the facility and shall deliver him to the court upon request or transfer him to the facility designated by the intake officer or the court, unless the court has waived its jurisdiction with respect to the person and he is being proceeded against as an adult.

(b) When a case is transferred to another court for criminal prosecution, the child shall promptly be transferred to the appropriate officer or adult detention facility in accordance with the law governing the detention of persons charged with crime.

(c) A child may not be transported together with adults who have been charged with or convicted of a crime unless the court has waived its jurisdiction and the child is being proceeded against as an adult.