There is no justification.
It turns out AK-47s with a sawed off barrel are all the rage with the teen aged gangster spray and pray who are committing a lot of the gangland drug related murders .
Let me ask for those statistics, how many people in this country have been shot by an AK-47? Must be thousands and thousands....
I will wait for the facts to become public before forming an opinion either way. Looks like a hard case with exceptional circumstances.
In answer to your question on the number of AK used in homicides, the number is less that 25 in a year when there were around 14,500 homicides- less than the number of people who were killed by being struck by lightning in the same time frame.
Use of rifles of any kind in killings (or any other crime for that matter) is very, very rare and many more people are killed with knives or bare fists than are killed by rifles.
SO this rampant all the rage gang weapon is not so rampant.