No that is the weird part. A body in Michigan was found then 2 weeks later in Iowa they found another body and that is where the Sinsinawa written.
Sinsinawa was the street in Michigan where the detectives think the body was put in the water.
Now that is another part that makes it weird. Reference at one murder scene to a location from the previous murder.
The REALLY weird part will be when they find a reference at the murder scene that refers to a location for a FUTURE murder. (Although they may not want to use something like “Sinsinawa”, but maybe something more like Maple Ave. and 5th Street.)