Police hope the messages will bring forward new evidence and eyewitnesses to the murder of John Hatch last year.
The phones have been identified as being in use on 16 December close to the route Mr Hatch travelled on the night he was killed.
About 7,500 people are expected to receive the messages asking them to contact police.
Dangerous offender
The messages will also direct people to a website to answer a few questions that the Ontario Provincial Police (OPP) said would help its officers.
