DSI originated in 1969 when Sheriff A.B. Clark started a security company in response to a request from
the construction company building the nearby Farley Nuclear Plant. As the company’s reputation grew
for providing quality security services DSI began to grow, opening an eventual 17 branch offices. This impressive growth history is punctuated with examples of versatility, flexibility, and sound management practices. A.B. Clark began DSI with the belief that his company could fill a void with a dependable, competent team of people. DSI now consists of thousands of carefully selected and highly trained security personnel.

DSI is still a family-owned and managed company, led by A.B.’s son Alan, Chairman of the Board, along
with his wife Marty, President. Alan and Marty’s three children all work with DSI in various capacities
as well. DSI has also benefited from its well-rounded, experienced, and professional management
staff that have helped in building DSI’s reputation as a leader in the security industry. Following sound
business practices through the years DSI has been able to maintain a high quality of clientele. Many
of our clients have experimented with less expensive security suppliers prior to choosing DSI, but have
ultimately chosen the more personal way of doing business DSI provides.