bugging
cloak-and-dagger work
counterespionage
counterintelligence
electronic surveillance
espial
following
intelligence
intelligence work
looking
lookout
military intelligence
note
notice
observance
observation
reconnaissance
regard
respect
secret police
secret service
shadowing
sleuthing
spying
stakeout
surveillance
tailing
trailing
viewing
watch
watching
wiretap
wiretapping
witnessing
undercover work
arson
assassination
assassinations
blackmail
bribery
coercion
conspiracy
disloyalty
felony
forgery
fraud
harassment
launder
perjury
piracy
sabotage
smuggle
spy
subversion
terrorism
treachery
undercover
vandalism