lögreglu

In a sentence

• Ég hef samband við lögreglu ef það er neyðartilvik.

  I contact the police if there is an emergency.

  In this sentence, 'lögreglu' is used in its accusative form as the direct object of the verb 'hef samband við' (contact).

• Það er mikilvægt að treysta lögreglunni.

  It is important to trust the police.

  Here, 'lögreglunni' is in the dative form with the definite article, as governed by the preposition 'að' (to).

• Lögreglan kom fljótt á staðinn.

  The police arrived quickly at the scene.

  In this sentence, 'Lögreglan' is the subject of the sentence in the nominative form with the definite article.