Others wondered whether she had deliberately disappeared.
There were questions about people she had encountered while traveling and about strangers who had interacted with her online.
Her public social-media history became part of the investigation.
That created both opportunities and problems.
Thousands of people began examining old photographs, videos, travel routes and comments.
Some observations were useful.
Others were completely speculative.
Investigators repeatedly had to separate genuine information from internet rumors.
That distinction became one of the most important lessons of the case.
A missing-person investigation cannot be solved simply by collecting theories.
It requires evidence.
The digital trail
Riley’s online activity provided investigators with a timeline of her movements.
Location information, messages, photographs and travel posts helped establish where she had been in the days before her disappearance.
But technology could not answer the central question:
Where had Riley gone?
Search teams examined the area around the abandoned van.
