What is the test for a plaintiff to prove that they were not involved in setting the law in motion?

In Petrovich v. Campbell, [1992] B.C.J. No. 20 (S.C.)(Q.L.), Mr. Justice Sheppard approved of the test for the first element of whether the proceedings were initiated by the defendant as set out in Fleming on the Law of Torts, 7th Ed., p. 582: To incur liability, the defendant must play an active role in the conduct of the proceedings, as by "instigating" or setting them in motion... The defendant must have been "actively instrumental" in setting the law in motion. Simply giving a candid account, however incriminating, to the police or magistrate is not the equivalent of launching a prosecution: the critical decision to prosecute not being his, 'the stone set rolling [is] a stone of suspicion only.'