Toronto police were investigating the existence of an alleged video involving Mayor Rob Ford several weeks before the story first appeared in the Toronto Star, CTV News has learned.

As part of the investigation leading to Thursday’s police raids in Toronto, Windsor and Alberta, officers obtained telephone wiretap evidence.

A highly-placed source confirms to CTV News that on those wiretaps, persons of interest discussed the video in detail, and referred to the mayor's presence in the video.

At a news conference Thursday, reporters asked police Chief Bill Blair about the use of wiretaps, but Blair said he cannot comment on the evidence or "investigative methodologies."

CP24 has not seen the video and cannot confirm its existence or authenticity.

The alleged video purports to show the mayor smoking from what appears to be a glass pipe.

On his May 26 radio show, Ford told a caller “there’s no video.”

The mayor has publicly denied using crack cocaine.

With files from CTV News

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