Bumping this case up.
This is all I could find on the internt, and it is dated 2 June 2005:
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Shelly or Michelle...
The Shiawassee County Sheriff's Department and the FBI searched property on Middleton Road near Hickory St. for the body of a woman. According to a statement released by the sheriff's department, investigators got the information from a convicted murderer but had not found the body.
Investigators said they are not releasing the name of the suspect in this case, even though he already has been convicted in one homicide, in order to protect his family from embarrassment and keep his cooperation.
They are looking for a white woman about 17 or 18 years old who was 5-foot-6-inches tall and weighed 140 pounds. Sheriff Jon Wilson said her name may have been Shelly or Michelle. She had shoulder-length sandy brown hair and wore large pink frame glasses, according to the statement from the inmate.
She was described as having frequented the Tap Room Bar (old Owosso Hotel) in Owosso and spent time at Henderson Park. She may have been employed for a time by a business in the "Dutchtown" area of Owosso, in the neighborhood of Chipman and Stewart streets. The victim was said to have spent time with people who drove muscle cars or "high rise" four-wheel drive pickups.
Anyone who has information about this case is asked to call Detective Sgt. David Kirk at (989) 743-2202, ext. 2224.
LINK:
http://groups.google.com/group/alt.prisons/browse_thread/thread/22ff961f52f04ed7/91b1183b2e57161b?q=%22Rachel+Mary+Scott%22#91b1183b2e57161b&ei=iGwTS6eaOpW8Qpmqic0O&sa=t&ct=res&cd=1&source=groups&usg=AFQjCNHcqjz2PfpU55eiUl239Re_zaKhuQ