SURVEIL
surveil, follow, survey
(verb) keep under surveillance; “The police had been following him for weeks but they could not prove his involvement in the bombing”
Source: WordNet® 3.1
Etymology
Verb
surveil (third-person singular simple present surveils, present participle surveilling, simple past and past participle surveilled)
(transitive, US) To keep someone or something under surveillance.
Usage notes
Found without any comment in major American dictionaries, and in some British dictionaries. Collins recognizes it as either American or British.
The 2015 edition of Fowler's Dictionary of Modern English Usage labels it as "mostly AmE". Unrecognized by OED.
Source: Wiktionary