Former RCMP commissioner Giuliano Zaccardelli made the "final decision" to issue a news release during the last federal election campaign about a criminal investigation into the actions of the former Liberal government, RCMP watchdog Paul Kennedy said Monday.

Kennedy, head of the Commission for Public Complaints Against the RCMP, made the conclusion in a report released Monday based on his 13-month inquiry into the income trust affair.

The affair dates back to November 2005 when then-finance minister Ralph Goodale announced the federal tax policy toward income trusts.

Prior to the announcement, there was a jump in trading in income trusts -- leading to suspicions that inside information may have been leaked.

As a result, Judy Wasylycia-Leis, the NDP finance critic, wrote to Zaccardelli, asking the RCMP to probe the matter.

The commissioner replied to the request in late December 2005, during the election campaign, and said that a criminal investigation was being launched.

In a press release by the RCMP, dated Dec. 28, 2005, the agency confirmed the investigation and named Goodale -- although the release stated that there was no evidence of wrongdoing or illegal activity on his part.

After the release, a small Liberal lead in public opinion polls was lost to the Conservatives -- who later went on to win the election.

Despite Zaccardelli's decision, Kennedy said Monday that the former commissioner didn't break any rules because the force had no rules in place.

"There is no evidence that Commissioner Zaccardelli relied on any improper considerations in coming to his decisions," Kennedy said in his report.

Still, Kennedy said it was "imperative" to do things differently in the future.

"I think what is required here is a more detailed map that shows the kinds of things that one has to consider before making a disclosure," Kennedy told CTV on Monday.

"In addition, because the public interest in having a free election is so important, my recommendation is that there be a presumption in favour of non-disclosure during the course of an election."

Zaccardelli did not cooperate with the inquiry so Kennedy said he hasn't got the "slightest idea" why he named Goodale in the press release -- a move contrary to past RCMP practice.

Goodale was eventually cleared of any wrongdoing in Feb. 2007.

A Finance Department bureaucrat, Serge Nadeau, was charged with breach of trust for allegedly using inside information to profit from income trust trading. He is yet to face trial on the charges.

With files from The Canadian Press