A Lack of Evidence
The biggest problem was the lack of evidence and witnesses. There were no fingerprints, no ransom, no weapons, and no body. All they had was a single thread and a shoeprint. Detectives went to countless shoe stores, trying to track down a tennis shoe that matched.
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For a while, the leading suspects were a teenaged neighbor who flirted with Ann Marie and her cousin (who later became a convicted child molester). Other suspects would surface over the years. In 1964, an auto parts salesman from Spokane was reported to have taken a 10-year-old girl from Tacoma on a ride in his Buick convertible.