A group of people move into an area, quietly.

The group becomes big enough to vote in one of their own.

That Politician appoints one of the group to a position of authority in the police

These two protect each other, and their group, to the detriment of the community at large

Members of their group begin terrorising the population under the protection of these two, they seek to convince the general population to
convert to their view
pay protection money
leave
or, suffer the consequences.

These are the tactics of the left, who follow the mafia principles - the mafia, created by islam.