55 ILCS 5/3-3024
When the jury are assembled, the coroner shall appoint one of the number as foreman, and administer to him an oath or affirmation, in the following form, to-wit:
You, as foreman to this inquest, do solemnly swear (or affirm, as the case may require), that you will diligently inquire, and true presentment make, how, and in what manner, and by whom or what, the body which lies dead, came to its death; and that you will deliver to me, the coroner of this county, a true inquest thereof, according to such evidence as shall be given you, and according to the best of your knowledge and belief; so help you God.
And to the other jurors, one as follows, to-wit:
The same oath which A B, your foreman has just now taken on his part, you and each of you do solemnly swear (or affirm, as the case may require), to keep on your respective parts; so help you God.
55 ILCS 5/3-3024