A Team Of Criminal Defence Attorneys. - 55+ Years Of Criminal Law Experience. At Der Barristers, we have the unique experience of knowing criminal law from both sides – defence and prosecution. As former Crown prosecutors, our lawyers have years of experience in criminal defence, trials and appeals, at all levels of court, including the Supreme Court of Canada. Senior lawyer Balfour Der Q.C., alone, has represented over 4,000 clients in his ten years as a prosecutor, handled hundreds of cases as a senior trial and appeals counsel. This extensive experience and proven track record equip us to fight any type of criminal charge, not only in Calgary, Alberta, but anywhere in Canada.