Complex sentence: The current Police Commissioner, or chief of police, is Darren L. Alston, serving his second term in that role, has been working for the department since 1993, and served various other roles such as captain, major, and deputy chief.
Split into simpler sentences: The current Police Commissioner, or chief of police, is Darren L. Alston, serving his second term in that role. He has been working for the department since 1993, and has served various other roles such as captain, major, and deputy chief.