Cult
A cult is often a small, newly started religious movement. Cults have beliefs or practices that many people think of as being odd, or that have practices that most people in the world do not practice.  More than that, cults have often been led by people who are not elected, and control the group according to their own wishes. Some cult leaders have been dangerous criminals (Charles Manson; Peoples Temple) or even lunatics. Killings and mass suicides have occurred in cults (Order of the Solar Temple; Heaven's Gate). Of course, a "suicide" enforced by armed guards carrying sub-machine guns (Peoples Temple; Movement for the Restoration of the Ten Commandments of God) is not a simple suicide as generally understood. It is at least an assisted and coerced suicide.