11/13/2013 12:04 EST | Updated 01/23/2014 06:58 EST

Robocalls investigator takes the stand

The lead investigator in the robocalls probe is taking the stand Wednesday as CBC News and other media outlets challenge a publication ban in the case.

Al Mathews, who has led the Elections Canada probe into misleading robocalls in Guelph, Ont., is being called to testify about the ban on the names of several witnesses interviewed in the case.

Both Mathews and Michael Sona, the only person charged in the case, are in the Ottawa courtroom for the hearing.