Advanced Investigative Services is a full service investigative and security agency that offers comprehensive investigative and security services throughout the state of Illinois, as well as the greater St. Louis, MO area, and specialized investigative services throughout the states of Illinois, Indiana, Kentucky, and MissouriWe pride ourselves on our timely and professional service, which is reflected in our outstanding reputation with our corporate clients, as well as with the numerous individual clients we have served. Our investigative and security staff, which has a primary base of current or retired local, state, and federal law enforcement officers, has in excess of 100 years of investigative experience.