Maj Md Nurul Mannan Choudhury (Retd.), CPP, MBA (HRM) is a visionary security consultant of Bangladesh and is founder Managing Director of Security Link Limited, former Managing Director Avant-garde Ltd., and former Director of Aegis Services Ltd., a sister concern of Square Group. Mr. Choudhury, in his military career, has served as instructor in various military institutions like Bangladesh Military Academy and Tactics Wing of School of Infantry and Tactics. He also conducted training for civil services officers and officers of Bangladesh Police. He also received training from College of Combat, India. As an infantry officer he served as company commander and staff officer of various headquarters and regiments of Bangladesh Army.

He designed integrated security as Consultant for Bashundhara Gold Refinery in Bangladesh. He took personal interest to advice on risk assessment, security designing, security system, policies and procedures for his clients like National Tele Monitoring cell, DGFI, The City Bank Ltd, DSE, Karnaphuli Fertilizer, Vivo phone BD, Xiaomi phone, OSJI bridge project, Jamuna Future Park, Apollo Hospital, Square Hospital, Square Textile, Square Fashions, Square Pharma, Lafarge Cement, BGMEA, Palace Resort and Spa, ISSIT, Grameen Phone, Prothom Alo etc.

Mr. Choudhury achieved Board Certification on security management and became a Certified Protection Professional (CPP) in 2009 from ASIS Intl. USA. He was President ASIS Dhaka Chapter 2021 and is Member of ASIS Asia Pacific Regional Board of Directors 2025.

Mr. Choudhury regularly takes classes for CPP and PSP preparatory courses, conducts security classes at Dhaka University, BUP. He takes keen interest in literary writings. He was a team member of research work on liberation war under supervision of 24 Infantry Division. His first book was published in 2005.