Michigan Compiled Laws, Chapters 760 to 777 Code of Criminal Procedure § 768.26

Sec. 26. Testimony taken at an examination, preliminary hearing, or at a former trial of the case, or taken by deposition at the instance of the defendant, may be used by the prosecution whenever the witness giving such testimony can not, for any reason, be produced at the trial, or whenever the witness has, since giving such testimony become insane or otherwise mentally incapacitated to testify.