Definitions of police
(trade mark law) actively maintaining rights to a trade mark by ensuring that no third parties use or register similar marks which may lead to consumer confusion
The company's failure to police its trade mark lead to a loss of trade mark rights.
to control the way in which a dangerous activity is carried out, the way a harmful substance is dealt with or the terms of an agreement (especially one between two contentious parties) are maintained
Even if the two countries cooperate, someone would still have to police the deal.
to regulate and control the maintenance of law and order in a state, a country or a community
Sunday's demonstration is expected to be heavily policed.