In Maryland, a Special Police officer is generally a person who has statutory authority of arrest at a specific location or property. One example would be a security guard at a shopping mall. If he or she has a Special Police Commision, he would have powers of arrest only on the mall's building and surrounding property. Another example in Maryland would be a baliff a certain district court houses. They are commisioned as Special Police Officers as well, and they have arrest powers only at certain specified locations. Think of it as Police Officer "Light". I'm sure others will chime in with details that I omitted, or with versions from other states or localities. I hope I've answered your question.
