Deadly Magical Power

All I have to do is paint a portrait of somebody being dead and he or she dies in real life.
I've painted portraits of my former boss, my in-laws and I also painted a portrait of my wife.
I've been given a magical power but I don't know where it came from.
My killing spree is not going to end, there will be more deaths to come.
I'm going to paint portraits of Hillary Clinton and Donald Trump.
Then I'll paint portraits of the creators of the new Doctor Who TV show, I'll get rid of all of those chumps.
I'm also going to paint a portrait of a bully who I went to school with.
He'd better enjoy what time he has left because he won't have long to live.
I will never see the inside of a courtroom, I will never be tried.
If you don't want your portrait to be painted, don't get on my bad side.