keep under surveillance

:  to retain in one's possession or power

:  to refrain from granting, giving, or allowing

:  to have in control

:  the means or provisions by which one is kept

:  one that keeps or protects: such as

:  fortress, castle

:  in or into a position below or beneath something

:  below or short of some quantity, level, or limit

:  in or into a condition of subjection, subordination, or unconsciousness

:  below or beneath so as to be overhung, surmounted, covered, protected, or concealed by

:  subject to the authority, control, guidance, or instruction of

:  receiving or undergoing the action or effect of

:  lower in rank or authority :  subordinate

:  close watch kept over someone or something (as by a detective)

:  supervision