The president of Calgary's police union who, along with another officer, is charged in an assault related to a traffic stop has a new lawyer.

Willie deWit was representing Sgt. Les Kaminski of the Calgary Police Association, but deWit was recently named a Court of Queen's Bench justice.

Alain Hepner will take over as Kaminski's defence counsel.

Kaminski is charged with assault with a weapon and perjury, while Const. Brant Derrick faces one count of assault causing bodily harm.

The case has been adjourned to April 20.

The charges stem from a 2008 traffic stop in downtown Calgary that ended in the arrest of Jason Arkinstall, who was charged with uttering threats against Derrick.

A provincial court judge acquitted Arkinstall in 2011 and said in his written decision that Kaminski and Derrick were not credible witnesses.

Kaminski became head of the 2,200-member police union earlier this year.