Mich. Comp. Laws § 764.1c: Issuing warrant or endorsing complaint if accused in custody upon arrest without warrant; finding of reasonable cause; endorsement as complaint and warrant.

Sec. 1c.

If the accused is in custody upon an arrest without a warrant, a magistrate, upon finding reasonable cause as provided in section 1a of this chapter, shall do either of the following:

Issue a warrant as provided in section 1b of this chapter.

Endorse upon the complaint a finding of reasonable cause and a direction to take the accused before a magistrate of the judicial district in which the offense is charged to have been committed.

As endorsed pursuant to subsection (1)(b), the complaint shall constitute both a complaint and warrant.