La policía arrestó al hombre.

In Spanish, la policía is usually a singular collective noun when it means the police force or the police as an institution. So it takes a singular verb:

• La policía arrestó... = the police arrested...

This is different from English, where the police normally behaves like a plural expression.

Also, policía is grammatically feminine as a noun in this meaning, so it uses la.

Because the subject is la policía, which is grammatically singular in this sentence.

So the pattern is:

• La policía arrestó... = singular subject + singular verb

If the subject were plural, the verb would also be plural, for example:

• Los policías arrestaron al hombre = the police officers arrested the man

Arrestó is the preterite tense, third person singular, from arrestar.

The preterite is used for a completed action in the past. Here, it presents the arrest as a finished event:

• arrestó = he/she/it arrested

In this sentence, it means:

• la policía arrestó = the police arrested

The accent mark shows the correct stress and also helps identify the verb form.

• arrestó = he/she/it arrested (preterite)
• arresto = I arrest (present) or arrest as a noun in some contexts

So the accent is important because it changes both pronunciation and meaning.

Because Spanish uses the personal a before a specific human direct object.

Here, the man is the person receiving the action of the verb, so Spanish requires a:

• arrestó a el hombre → this contracts to arrestó al hombre

So al here is simply:

• a + el = al

This is one of the most common things English speakers need to get used to, because English does not have an equivalent structure.

No. Al hombre is still the direct object.

The a here is the personal a, not a sign of an indirect object.

So in:

• La policía arrestó al hombre

the roles are:

• La policía = subject
• arrestó = verb
• al hombre = direct object

This can be confusing because English learners often associate a with to, but here it does not mean to the man.

Yes. Policía can mean either:

• the police / the police force as a collective idea
• a police officer

The article and context tell you which meaning is intended.

For example:

• La policía arrestó al hombre = the police arrested the man
• El policía arrestó al hombre = the male police officer arrested the man
• La policía arrestó al hombre can also sometimes mean the female police officer arrested the man, but in many basic-learning contexts it is understood as the police as an institution

So context matters.

It is correct and fully understandable, but in Spain, detener is often more common in news reports or formal contexts.

For example:

• La policía detuvo al hombre = the police detained/arrested the man

So arrestar is grammatical and clear, but detener may sound more typical in many Spain-Spanish contexts.

Normally, no. In standard Spanish, you would usually need the article here:

• La policía arrestó al hombre

Leaving out the article sounds incomplete or unnatural in this sentence.

Spanish uses the definite article more often than English in many cases, and with a noun like policía in this meaning, the article is expected.

The normal, neutral word order is:

• La policía arrestó al hombre

That is the most natural order for a simple statement: subject + verb + object.

Spanish word order can sometimes change for emphasis or style, but this sentence is the standard and easiest version for learners.

Because al only replaces a + el. It does not change the noun itself.

So:

• el hombre = the man
• a el hombre → al hombre

The noun hombre stays exactly the same. Only the preposition a and the article el combine into al.

Potentially, yes, depending on context, because la policía can also refer to a female police officer.

So out of context, la policía may be interpreted as either:

• the police as a collective institution, or
• the policewoman

However, in many beginner examples, it is often intended as the police. If you wanted to be clearly singular and refer to one officer, context usually makes that clearer, or a different wording may be used.