The attack was cited as one of a number of incidents in which mentally disturbed individuals launched violent attacks under the justification of Islamist ideas or slogans . Other examples include Man Haron Monis , the gunman in the 2014 Sydney hostage crisis ; and Michael Zehaf-Bibeau , the perpetrator of the 2014 shootings at Parliament Hill , Ottawa . According to psychologists and psychiatrists who study radicalization , jihad propaganda and calls to kill infidels can push mentally disturbed individuals to act , even in the absence of direct or personal contact with radical Islamists
2014 shootings at Parliament Hill , Ottawa
2014 shootings at Parliament Hill, Ottawa
2016 Munich knife attack