Md. Rule 4-644
Rule 4-644. Record and File
(a) Record of Subpoena. The clerk of the circuit court shall maintain a record of each subpoena issued by the clerk in a criminal investigation and the return on it.
(b) File. Upon the filing of any pleading, motion, or paper other than a witness subpoena and return, the clerk shall establish a file for the criminal investigation and designate the case as “In Re Criminal Investigation No. _____, in the Circuit Court for _______.”