Mo. Rev. Stat. § 532.200: The body to accompany the return.

If any officer or person upon whom a writ of habeas corpus shall have been served shall have in his custody or power, or under his restraint, the party for whose benefit the writ was awarded, he shall also bring the body of such person before the court, according to the command of the writ, and within the time herein specified for making return, except in case of sickness of such person, as herein provided.