Welcome to United Sentry Security Services California's Premier Private Security Group We provide: A Team of Elite armed, unarmed, uniformed or plain clothes long term & temporary Security Officers with 22 years of Military and Private Security experience. We offer a fine-tuned security service that caters to a wide variety of needs. Every United Sentry Employee undergoes and must pass a rigorous personal interview, have a clean background check, drug test, have Military-Standard training and routine periodic competence review.