Both cases involve attractive, sober women in their early twenties who went missing from music centered parties in the wee hours. The location of the party from which Grace went missing is about 29 miles from the Halloween party from which Chelsea went missing.
I've placed a marker on the Chelsea Case Map at the location of the party, with this caption:
500 Temple St, Detroit, MI 48201 |||| Police issued a missing-person notice for a 20-year-old Saginaw woman last seen early Tuesday [5/26/15] morning at a Movement after-party at the Detroit Masonic Temple. Grace Martinez was separated from her friend and last seen at about 3 a.m., talking with a man who appeared to be about 40, with brown hair and eyes, clean shaven and wearing a blue dress shirt... . per Robert Allen, Detroit Free Press article: http://www.freep.com/story/news/loc.../27/missing-movement-masonic-temple/28017289/ |||| No link has been established to the Chelsea case.
Chelsea case map link:
https://www.google.com/maps/d/edit?mid=zvYyF06zvqck.kaQX8kDx9-8w
In looking for the address of the party, I found two sites for the "Movement After-parties" organizaton that hosted the party. Neither has yet posted anything about Grace's disappearance. Might someone from the thread give "Movement" a heads up, please? Lacking a Facebook account, I wasn't able to.