''Like a thief in the night''

''Special reconnaissance (SR) is defined as reconnaissance and surveillance actions conducted by Special Forces (SF) to obtain or verify, by visual observation or other collection methods, information concerning the capabilities, intentions, and activities of an actual or potential enemy or to secure data concerning the meteorologic, hydrographic, geographic, or demographic characteristics of a particular area. It includes target acquisition, area assessment, and poststrike reconnaissance.''

FM 31-20-5 Special Forces Reconnaissance Tactics,Techniques,& Procedures (1990)

https://archive.org/details/milmanual-fm-31-20-5-special-reconnaissance-tactics-techniques--proced