55 ILCS 5/3-3026
The coroner shall have power to summon, or cause to be summoned, and compel the attendance of all such witnesses whose testimony may probably be requisite to the proving of any fact or circumstance relating to the object of such his inquest, and to administer to such witnesses the proper oath.
If the coroner is unable to secure records or documents he deems necessary to complete the investigation required by Section 3-3013, or for the establishing or proving of any fact or circumstance relating to the object of his inquest, he shall appear before the circuit judge of the county for which he is coroner and, upon good cause shown, said judge shall issue a subpoena for the delivery to the coroner of the documents or records requested.
55 ILCS 5/3-3026