The young girl was kidnapped near her family's Salt Lake apartment in 1995.
Her body was found floating in a canal off the Jordan River near 1900 South 1600 West the same day she was taken.
A neighbor claimed he was up early and saw a teenager coming from the same direction as the canal. At first, he thought the teen was wearing pants with two different colors, but then realized the pants were wet, a press release stated.
It's been almost two years since investigators announced new leads in the case.
The witness described the teenager as a 16- to 17-year-old boy who is Hispanic, had a slight build and a narrow face with high cheek bones. He was seen wearing denim jeans, a white shirt and a medium length gold chain.
The witness had previously been in contact with the Salt Lake City Police Department, but didn't sit down with a sketch artist. Police previously released a sketch of a potential suspect. That man was never identified.
The Tapia family plans to visit the cemetery where Rosie was buried.