Ok,You Having Hard time Having ideas,i Have Some .You're a Security Guard in a Mall .the Mall is Insiperd in the 80's and 90's Malls .The Killer is Inspired in the Zodiac Killer(Would Have Papers Around the Mall,Containing Misterious Cypher). .In the 1980's The World was an Cold war,The Killer Would Represent the Communist Threat From that time.