Canadian police have retrieved a video allegedly showing Toronto mayor Rob Ford smoking crack cocaine during an investigation that led to the arrest of Alessandro Lisi, a friend and occasional driver for the 44-year-old politician.

Toronto police chief Bill Blair said that Ford was trailed by detectives during an investigation sparked by media reports that the flamboyant mayor was under the influence of drugs in a 90-second video that was in the hands of suspected criminal gang.

"It's fair to say that the mayor does appear in that video but I'm not going to get into the detail of the activities depicted," Blair said. He added, however, that the footage was "consistent with what had been previously described in various media reports".

The scandal erupted earlier this year when US website Gawker and newspaper Toronto Star reported they had been separately offered a video by a Somali drug gang for a six-figure sum.

Gawker editor John Cook and Toronto Star reporters Robyn Doolittle and Kevin Donovan claimed they were shown the recording on a mobile phone and were left in little doubt that it showed Ford inhaling from what looked like a glass pipe and making erratic comments.

Ford, who was elected mayor in 2010, denied the allegations.

Police launched a probe into the allegations. Lisi was arrested on charges of marijuana trafficking and possession charges and granted bail but was rearrested on an additional charge of extortion.

Documents released included information about the retrieval of the video and accounts of Ford's meetings with Lisi.

The documents show Ford receiving suspicious packages from Lisi on several occasions.

"Lisi approached the driver's side of the mayor's vehicle with a small white gift bag in hand; he then walked around to the passenger side and got on board," reads one document dated 30 July, 2013. "After a few minutes Lisi exited the Escalade empty-handed and walked back to his Range Rover."

Another file, dated 13 August, details a one-hour meeting between the two.

"[They] made their way into a secluded area of the adjacent woods where they were obscured from surveillance efforts and stayed for approximately one hour," the document reads.

Blair said the video was retrieved on a computer but did not provide further details.

He said he was "disappointed" after viewing it. There was nothing in it that would provide grounds to press charges against Ford, he said.

Ford reacted angrily and refused to answer questions when confronted by reporters outside his home.