警官は泥棒の腕をつかんだ。

policeman

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

thief; burglar; robber; theft

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

arm; skill; efforts; ability

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to seize; to catch; to grasp; to grip; to grab; to hold; to catch hold of; to lay one's hands on; to clutch; to understand; to grasp; to comprehend