Diamond Security & Investigative Services is joining Citadel Security

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For nearly 30 years, Diamond Security & Investigative Services has served clients across Oklahoma with a commitment to professionalism, accountability and dependable service.

Now, through our partnership with Citadel Security, we’re building on that foundation with expanded resources, capabilities and operational support while maintaining the local leadership and service clients know and trust.

WHY CITADEL SECURITY

A Stronger Foundation for Trusted Security

A partnership focused on continuity, strength, and service

Diamond clients will continue to receive the responsive, locally accountable service they expect, now supported by Citadel’s expanded operational resources, technology, training and compliance support.

Together, Diamond and Citadel offer:

  • Armed and unarmed security officers

  • Private investigations

  • Background screening

  • Security consulting

  • Mobile patrol services

  • Security technology and monitoring

  • Expanded training and compliance resources

  • Scalable security programs for multi-site organizations

Together, we serve commercial, industrial and manufacturing, healthcare, government, residential, construction and event environments across Oklahoma.

Whether you already work with Diamond or are looking for security services, our team is ready to help.

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About Citadel Security

18

Years in Business

400+

Clients Served by Citadel Today

$10+

Billion in Assets Protected

95%

+ Client Retention Rate

Why Citadel

Raising the Standard in Security

Rooted in Community

Our officers serve with professionalism and care—building trust while safeguarding the communities we protect.

Veteran-Led Mission Focus

 Founded and led by U.S. military veterans, Citadel brings a disciplined, mission-first approach to every engagement.

Engineered for Responsiveness

With empowered regional offices and 24/7 support, we respond quickly and adapt to evolving client needs.

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Ready for Reliable, Responsive Security?

Whether you’re facing growing safety concerns, managing high-traffic property, or simply ready to raise the standard, we’re here to help. Let’s discuss how Citadel’s proactive, professional approach can support your goals and safeguard your operations.