personnel security investigation

security сlearance check investigation

servicing personnel / maintenance personnel

Federal Bureau of Investigation (FBI)

International Independent Investigation Commission - Lebanon (UNIIIC)

investigation and intelligence unit (law enforcement)

US Army Criminal Investigation Command

systematic investigation

targeted investigation

accident investigation

Accident Investigation and Prevention Section

accident investigation authority

accident investigation division

crash investigation procedure

safety investigation

safety investigation board

field investigation

air accident investigation

incident investigation

investigation anatomy

investigation authority

investigation tests

postflight investigation

space geological investigation

state conducting investigation

state instituting the investigation

investigation

background investigation

investigation branch

investigation unit

social security for military personnel

security agreement (information security, NATO)

acquisition of personnel