By Holly Menino

SPRINGFIELD, Ore. -- A cold case has stumped area detectives for 15 years, and has one Springfield man's family looking for answers.

Ronald Dale Willis was last seen on March 20, 1995. His car was found abandoned on the side of Interstate 5 near Albany by police, and since then remains one of the only clues into Willis' disappearance.

Before his disappearance, Willis, 32 at the time, was working as a mechanic after his discharge from the military. His sister, Jeannie Garms, says Willis was having marital issues and was using drugs during the time leading up to his disappearance.

Over the years, several tips were called in relating to Willis, but they all lead to dead ends. A private investigator, hired in 2004, came up empty-handed as well. In 2007, there was even a tip that Willis had been buried in the backyard of his previous home, but no body was found.

Police say at this point there is no crime involved in Willis' disappearance. If you've seen him, call the Crimestoppers line at 1-800-3-DETECT.