La policía encontró la droga.

Because la policía here means the police as an institution or force, not a male police officer.

• la policía = the police
• el policía = the policeman / police officer
• la policía can also mean the policewoman, depending on context

In this sentence, la policía encontró la droga, la policía is a singular collective noun referring to the police force.

In Spanish, la policía is usually treated as a singular noun when it means the police force. So the verb is singular too:

• La policía encontró... = The police found...

This is different from English, where the police normally takes a plural verb:

• The police found...

So even though the meaning matches English the police, the grammar does not.

Encontró is the preterite form of encontrar.

It means found in the sense of a completed action in the past.

• encontrar = to find
• encontró = he/she/it found, or you found (formal singular)

In this sentence, it means:

• La policía encontró la droga = the police found the drugs/drug

The preterite is used because the action is seen as finished.

The accent mark in encontró shows both pronunciation and meaning.

It helps distinguish between:

• encontro — not a standard finite form here
• encontró — he/she/it found or you found (formal singular)

The stress falls on the last syllable: en-con-TRÓ.

This accent is an important part of the spelling, not optional.

Spanish often uses the definite article (el, la, los, las) more often than English does.

So la droga means the drug or the drugs, depending on context. In many basic examples, it is translated naturally as the drugs if that fits the situation better.

The article is needed here because Spanish normally does not say just encontró droga in the same neutral way English can sometimes say found drugs.
Compare:

• La policía encontró la droga = the police found the drug / the drugs
• La policía encontró droga can exist, but it feels more like found drugs / found some drugs / found narcotics in a more indefinite or substance-focused sense

Because the personal a is mainly used before specific human beings (and sometimes pets or personified beings).

Examples:

• Veo a María.
• La policía arrestó a un hombre.

But la droga is a thing, not a person, so there is no personal a:

• La policía encontró la droga.

Yes. That would be the present perfect:

• La policía ha encontrado la droga = the police have found the drug(s)

In Spain, the present perfect is often used for past actions connected to the present, especially with time expressions like hoy, esta semana, etc.

But encontró is the preterite, which presents the event more simply as a finished past action.

So both are possible, but they do not feel exactly the same.

Sometimes, yes, depending on context.

Grammatically, la droga is singular in Spanish. But in English, the most natural translation might be:

• the drug
• the drugs

Why? Because drug and drugs are used a bit differently in English depending on context, and Spanish examples often use a singular noun more generally.

If the meaning has already been given to the learner, then the key grammar point is simply that droga is grammatically singular feminine here.

Word order matters a lot here because Spanish does not mark the object with a special ending.

• La policía encontró la droga = the police found the drug
• La droga encontró la policía would mean the drug found the police, which is not the intended meaning

Spanish does allow some flexibility in word order, but if you change the order, you usually need a clear reason or extra structure. The normal, neutral order is:

• subject + verb + object

So this sentence is in the most standard order.

A simple pronunciation guide is:

lah poh-lee-THEE-ah en-kon-TROH lah DROH-gah
in most of Spain

In much of Latin America, policía is more like:

lah poh-lee-SEE-ah

A few notes for Spain Spanish:

• c before i in policía is pronounced like th in thin
• ó in encontró is stressed on the last syllable
• g in droga is a hard g, like in go

Because the noun policía is feminine when it means the police force:

• la policía

This grammatical gender does not mean the police are female. It is just the gender of the noun.

Spanish nouns have grammatical gender, and adjectives/articles must agree with them. So you say:

• la policía
• not el policía when you mean the police force

If you meant the police officer, then the gender depends on the person:

• el policía = male officer
• la policía = female officer

So context is very important with this word.