Politiet fant fingeravtrykket.

In Norwegian, politiet is the usual word for the police as an institution. Grammatically, it is treated as a singular neuter noun, even though in English the police takes a plural verb.

So:

• Politiet fant ... = The police found ...
• literally, it behaves more like the police force in English

That is why you get fant and not a plural verb form.

Fant is the past tense (preterite) of finne, which means to find.

The main forms are:

• å finne = to find
• finner = find / finds
• fant = found
• har funnet = have/has found

So:

• Politiet fant fingeravtrykket. = The police found the fingerprint.

In Norwegian, the definite article is often added to the end of the noun instead of being a separate word before it.

Here:

• fingeravtrykk = fingerprint
• fingeravtrykket = the fingerprint

So the -et at the end means the.

This is very common in Norwegian:

• et hus = a house
• huset = the house

Because fingeravtrykk is a neuter noun.

For many neuter nouns, the pattern is:

• et fingeravtrykk = a fingerprint
• fingeravtrykket = the fingerprint

So the ending -et marks the definite singular form of a neuter noun.

Yes. Norwegian very often combines words into a single compound noun.

Here:

• finger = finger
• avtrykk = print / impression / mark
• fingeravtrykk = fingerprint

This is completely normal in Norwegian. English sometimes uses one word, two words, or a hyphen, but Norwegian usually prefers one compound word.

This is the normal Norwegian word order for a simple main clause:

subject + verb + object

So:

• Politiet = subject
• fant = verb
• fingeravtrykket = object

This is the same basic order as English in a sentence like The police found the fingerprint.

You would use the present tense form finner:

• Politiet finner fingeravtrykket. = The police find / are finding the fingerprint

In many contexts, though, the past tense fant is more natural if the action is already completed.

A simple learner-friendly guide is:

• Politiet ≈ po-lee-TEE-uh
• fant ≈ fahnt
• fingeravtrykket ≈ FING-er-av-TRIK-eh

A few notes:

• The stress in politiet is on the last main syllable: -ti-
• g in finger is pronounced
• The final -et in fingeravtrykket is usually a light unstressed ending

Pronunciation varies somewhat by dialect, but this will help you say it understandably.

Yes, but it changes the meaning.

• Politiet fant fingeravtrykket. = The police found the fingerprint.
• Politiet fant fingeravtrykk. = The police found fingerprint(s) / found fingerprints.

Without -et, the noun is indefinite, so it sounds less specific. The sentence you were given refers to one specific fingerprint.

Yes, Norwegian can do both.

• politiet = the police, the police force, the police as an institution
• en politimann = a police officer / policeman
• en politibetjent = a police officer
• to politibetjenter = two police officers

So Politiet fant fingeravtrykket focuses on the police as a group or authority, not on naming individual officers.