Recent vote against parts of the Anti-Terrorism Act has had no impact on the continuing Air India investigations, according to Liberal leader Stephane Dion, but police claimed otherwise.

After the Liberals joined the NDP and Bloc Quebecois in forcing the expiry of provisions in March of the act dealing with investigative hearings and preventive arrests, the head of the Royal Canadian Mounted Police in British Columbia told The Vancouver Sun the case had suffered "a serious and damaging blow".

Under the hearings provision, brought in by the previous Liberal government and upheld by the Supreme Court of Canada as constitutional, police had the power to call people believed to have information about an act of terrorism to answer questions before a judge. Deputy Commissioner Gary Bass said police had been preparing for more than two years to use one of the defeated provisions, investigative hearings, to advance the criminal case.

"While I do not dispute that the vote on this critical issue involved perhaps valid considerations beyond the Air India investigation, without doubt, it represents a serious and damaging blow to the interests of the families in this case," Bass said.

Dion admitted he has never asked for, nor received, a briefing from the RCMP on its probe into the bombing that killed 331 people, but said, "My answer is that it did not hurt the investigation."

Dion confirmed he has never spoken to the RCMP about the biggest criminal case in the country's history. "I have received a briefing note on the Air India investigation, but I received a briefing about the usefulness of these two clauses and I concluded that they were not useful, especially not for things that happened in the past because the intention was to investigate -- to prevent -- some thing that may come in the future," Dion said.

He said the investigative hearing provision had never been used in connection with Air India. Reminded that an investigative hearing had in fact been convened in British Columbia in 2003 and only adjourned when the person called -- the wife of the only man convicted in the bombing plot -- took her plight to Canada's highest court and later lost, Dion said the two lost portions of the act "were never used in a useful way, not at all."