"All of his fans, all over Quebec, but also his fellow singers (of whom I am one) hope to see him again alive!!! Come on my GuyBol, come out of your hiding place," one member wrote.
"Hot zones" lingering more than two days after the train derailment hampered authorities' efforts to search for missing people.
Forensic specialists have asked victims' families for hair samples, clothing, anything to help identify their loved ones.
In a town of just 6,000 residents, most everyone is affected by the deaths and destruction.
Prime Minister Stephen Harper has described the scene as a "war zone."