Learn Icelandic: Lögreglan hlýtur að hafa ásakað saklausan mann. - The police must have accused an innocent man.

When making a logical deduction about the past, Icelandic uses the present tense of hljóta (hlýtur) because you are making the conclusion right now. The past action is expressed by adding að hafa followed by the supine verb form (ásakað), matching the English structure "must have accused."

In English, "police" is often treated as plural. Why does it take the singular verb hlýtur here?

In Icelandic, lögregla (police) is a singular feminine noun. Because it represents the police force as a single collective unit, it always takes grammatically singular verbs.

Why do we use the accusative form saklausan mann here?

The verb ásaka (to accuse) governs the accusative case for the person being accused. Therefore, maður changes to its accusative form mann, and the adjective gets the strong masculine accusative ending, becoming saklausan.

Since this is about the police, why use ásakað instead of kært?

ásaka means "to accuse" or "to suspect" in a general or moral sense. If the police had formally pressed legal charges against the man, you would use the verb kæra (to press charges / to sue), which would make the supine form kært.