If the evidence of any witness implicates any person as the unlawful slayer of the person over whom the inquest is held, the coroner shall recognize such witness in such sum as he may think proper, to be and appear at the Circuit Court for the county on a designated day, within 30 days from the date of the recognizance, or as soon after such designated day as the court is in session, there to give evidence of the matter in question, and not depart without leave.