The Nazi anthem was the Horst-Wessel Lied (which was really a song lauding the Brownshirts), and the German national anthem was Das Lied der Deutschen (The Song of the Germans), otherwise known as the Deutschlandlied (Germany Song), and sometimes called after its first line, which is Deutschland, Deutschland über Alles (Germany, Germany above All). The words to the anthem were written by August Heinrich Hoffmann von Fallersleben in 1841, and set to a tune by Haydn. It was also the anthem of the Weimar Republic, so in no way can be considered distinctively Nazi.
The third verse of the Deutschlandlied is the current, official anthem of reunited Germany.
So whatever this biker-murderer was singing, it was on his part an affectation, having little to do with Germany.
Of course, Canada has no death penalty. It would be too cruel, I suppose. Certainly seems appropriate in this case. I think Texas has the right idea. And if you are in a gang, it does not matter exactly who pulled the trigger.
How could the perps think that they could ever get away with this? I suspect that it is partly because of the soft attitude of Canada toward murderers.
By the way, you might want to check out the crime rate in Canada: for the most part, they are such nice people, and so concerned about gun safety that it is very awkward to own or practice with firearms, and the official position is that it is unthinkable that you should ever defend yourself with a firearm. They are so tender-hearted, and yet the crime rate is just about double what it is in the States, and has risen in the last decade.