Any police force organized or existing by authority of the laws of this state in any city having a population of over one hundred thousand inhabitants is hereby authorized and empowered to form a relief association under the general incorporation laws of this state, and to create a fund for the purpose of affording relief to such members of their organization as may become sick or disabled while in the discharge of their duties, or who may become incapacitated by long years of service, and for aiding the families of police officers who may die while in the service of any police department, and for such other similar purposes as may be set forth in their articles of incorporation.