Yes, indeed, it is the policy of the government. In fact, the Criminal Code gives the authority to the government to investigate and prosecute anyone who abducts a Canadian anywhere in the world. The responsibility to lead the investigation and to do any prosecution falls upon the RCMP. As you mentioned, charges have been laid against Ali Omar Ader for his alleged role as a negotiator in the hostage-taking of Ms. Lindhout in 2008.
On October 5th, 2017. See this statement in context.