Here is a case which seem to have some possible connection to Cynthia Coon's disappearance.
Dawn Louise Basom, 13, Murdered 16 April 1969, Ypsilanti, Michigan
At 6:30 a.m. on April 16, the body of a 13-year-old schoolgirl named Dawn Louise Basom was found discarded beside a desolate road in Ypsilanti. Clothed only in a white blouse and bra, which had been pushed around her neck, she had been repeatedly stabbed in the chest and genitals, had received multiple slash wounds across the breasts, buttocks and stomach, then strangled to death with a two-foot length electrical flex still knotted around her neck. A handkerchief found stuffed in her mouth had likely been placed there to muffle her cries throughout her torture, and her murderer had placed her body in a location where rapid discovery was assured.
Investigators found no definite evidence Basom had been subjected to a sexual assault prior to her murder.
Basom had last been seen alive at 7:30 p.m. the previous evening, walking home from a friend's house located barely a mile from her own home. She had been accompanied part of the way by a friend named Earl Kidd, who informed police he and Basom had parted company at a desolate road just five blocks from her home, where Basom had begun walking alone alongside railroad tracks toward her home. One eyewitness reported seeing the girl minutes thereafter, at approximately 7:35 pm, although her movements thereafter were never verified.
The orange mohair sweater belonging to the victim was found in a deserted farmhouse just 100 yards from the desolate road on which her body had been placed after her murder. Glass particles found within this basement were of a similar consistency to those found upon the soles of Basom's shoes.
Upon conducting a search of the basement of this farmhouse, investigators discovered a further garment of her clothing, a length of electrical flex of the same type used to strangle the victim, and fresh human bloodstains, indicating this location as being the site of Basom's murder.
One week after the murder of Dawn Basom, a detective conducting a routine examination of this farmhouse basement discovered a scrap of cloth from Basom's blouse, plus an earring later determined to belong to Maralynn Skelton. Each item had been deliberately placed in this location, indicating that the murderer had returned to the scene of the crime, and a definite link between both homicides. (The farmhouse itself was destroyed in an act of
arson on May 13; when the fire was extinguished, five clipped lilacs were found arranged in an even row across the driveway to the building, leading investigators to theorize they had been placed there by the murderer to symbolize each victim.)
Investigators believed that Dawn was the victim of John Norman Collins, however he was never charged with her murder and it remains officially unsolved.