Today is the 20th anniversary of the disappearance of 13-year-old Philip Cairns from near his south Dublin home, but his family and detectives are still hopeful of discovering what happened the schoolboy.
Philip disappeared while walking back to school after lunch at his home in Rathfarnham.
A Garda inquiry was opened amid unprecedented public interest and assistance, but extensive inquiries failed to reveal the mystery of Philip's disappearance despite the case remaining a "live" file with detectives.
Six days after his disappearance, Philip's school bag was found in a nearby laneway which had been previously searched. Detectives hope new DNA-testing techniques applied to the bag could reveal a crucial clue.
Three schoolbooks were missing from the bag, and its appearance at a location which had been already been searched has led detectives to believe that it may have been placed there.
Det Sgt Tom Doyle said yesterday he hoped the new DNA test may help establish who had touched the bag. He suggested a school pupil at the time or an adult may have removed the bag from another location and appealed for anyone with information to come forward.
Speaking on behalf of his family yesterday, Philip's younger brother, Eoin, appealed for anyone with information about his brother's disappearance to get in touch with the gardaí.