On Saturday, October 30th, 2017 one man who adopted Canada as his home, he did not like polytheism. He believed that other faith groups were worshiping a false god and must be killed. He decided to kill others.
On Sunday, October 01st, 2017 a news broke out that a man with several assault rifles in Las Vegas began to open fire on people randomly and killing them.
Therefore, people who are unstable, they come in many shapes and forms. Simply they need an idea to justify their brutality.