Toronto police used air surveillance as part of their investigation into some associates of Mayor Rob Ford, the Globe and Mail has confirmed.
The revelation comes just days after Mr. Ford's friend and occasional driver Alexander 'Sandro' Lisi, 35, was arrested in a drug raid, part of a broader police investigation by two of Toronto police's lead investigators that has extended into the mayor's office.
Asked if he had any response to the report that his friends had been followed by a Toronto police airplane, Mr. Ford replied: "Any other questions?"
An aide then hustled him away from the media. "Okay, thank you very much. Media is being asked to leave. Tour's over," said Amin Massoudi, his special assistant for communications.
The media had been following Mr. Ford on a guided tour of this weekend's Austin City Limits festival.
Earlier this week, when asked whether he was concerned that police surveillance of Mr. Lisi may have picked up his communication with him, Mr. Ford shook his head and did not respond.
In a news conference on Wednesday, Mr. Ford described Mr. Lisi as a friend and called him a "good guy." The mayor said he was surprised by Mr. Lisi's arrest. Mr. Lisi faces four criminal charges including marijuana trafficking.
At least five former staffers from the mayor's office have been questioned about attempts to retrieved an alleged video of Rob Ford that appears to show the mayor smoking crack cocaine. Mr. Ford denies that the alleged video exists, and has said "I do not use crack cocaine."
With files from Marcus Gee in Austin