Such boards shall have all of the powers given by the general statutes to boards of police commissioners, shall have general management and supervision of the police department of such town and of the property and equipment used in connection therewith, shall make all needful regulations for the government thereof not contrary to law and may prescribe suitable penalties for the violation of any such regulation, including suspension or removal from office of any officer or member of such police department. Such board shall have the sole power of appointment, promotion and removal of the officers and members of such police department, under such regulations as it adopts for the purpose, and such appointees shall hold office during good behavior and until removed for cause upon written charges and after hearing. The members of such police department shall have all such authority with respect to the service of criminal process and the enforcement of the criminal laws as is vested by the general statutes in police officers and constables.