Our Contributors

Who writes for ClearanceJobsBlog?

Marko Hakamaa served in various military police positions with the United States Army worldwide for 22 years before retiring in 2006 as a Master Sergeant. Afterwards, he transitioned into the civilian workforce as a contractor background investigator for the Office of Personnel Management (OPM) before entering civil service as a Security Specialist in 2009.


Lindy Kyzer, is the Director of Content and PR at ClearanceJobs.com, the largest security-cleared job board, specializes in defense jobs for professionals with security clearances.  Before joining ClearanceJobs.com, she  worked as a public affairs specialist with the Department of the Army, working at Fort Eustis, Va. and then settling at the Pentagon in a media relations position.  She launched the U.S. Army into the social media space, developing the Army’s social media presence and strategy and spearheading the education of Army leaders on social media topics.

Highlights of her time with the Army included developing social media training for the Army Senior Leader Development Program for the Army’s most senior general officers, and providing social media training to over 1,000 incoming commanders at the Army’s Pre-Command Course for incoming battalion and brigade commanders at Fort Leavenworth, Kansas.


William Henderson, author of Security Clearance Manual, is a retired federal investigator who worked as a field agent and supervisor for the Defense Investigative Service (DIS) and its successor organizations, the Defense Security Service (DSS) and the Federal Investigative Services Division of the Office of Personnel Management (OPM) for over 20 years. He was previously an Army Counterintelligence Agent and a security manager at the Satellite Control Facilities Operation of Ford Aerospace & Communications Corporation.

He wrote his first personnel security investigation report in 1970 for the U.S. Army. His assignments included CI Special Operations in Japan and Korea, Source Administration in Vietnam, CI field office duty in Chicago, tactical CI operations in Colorado Springs, and a position on the J2 staff at CINCLANT.

While with DIS, DSS and OPM, he held assignments as a Special Agent, Senior Resident Agent, and Assistant Special Agent-in-Charge. His duty station was in Monterey, California where he conducted numerous security investigations of former Soviet Bloc Émigrés And Refugees teaching at the Defense Language Institute. He also frequently conducted investigations in major metropolitan areas throughout the United States.