Buscamos otro indicio con la linterna ultravioleta.

It can mean either, depending on context.

In Spanish, the simple present often covers both:

• we look for
• we are looking for

So Buscamos otro indicio... can mean:

• We look for another clue...
• We’re looking for another clue...

Spanish does have a progressive form, estamos buscando, but it is used less often than English are looking. In many everyday situations, buscamos sounds completely natural.

Because Spanish usually leaves out subject pronouns when the verb ending already shows who the subject is.

Buscamos clearly means we look / we are looking, so nosotros is not necessary.

You could say:

• Nosotros buscamos otro indicio...

But that would usually add emphasis, contrast, or clarity, for example:

• Nosotros buscamos otro indicio, pero ellos revisan la puerta.

So in a neutral sentence, leaving out nosotros is the normal choice.

Because otro normally does not take un before it.

So Spanish says:

• otro indicio = another clue
• not un otro indicio

This is a very common rule:

• otra vez = another time / again
• otro día = another day
• otra pregunta = another question

A useful shortcut is: if English has another, Spanish often just uses otro / otra by itself.

Because otro normally goes before the noun.

So:

• otro indicio is correct
• indicio otro is not natural here

Words like otro, mismo, primer, segundo, and many determiners usually come before the noun.

Also, otro functions a bit like another in English, so it naturally introduces the noun:

• otro libro
• otra pista
• otro indicio

Both can relate to a clue, but they are not always identical.

• indicio often means a sign, indication, or piece of evidence suggesting something
• pista often means a clue in a more practical or investigative sense

In detective-type contexts, both can appear, but indicio can sound a bit more formal or forensic.

For example:

• Hay indicios de que alguien entró por la ventana.
  = There are signs / indications that someone came in through the window.

• La policía encontró una pista importante.
  = The police found an important clue.

So in this sentence, indicio gives a slightly investigative, evidence-based feel.

Here con means something like with in the sense of using.

So:

• con la linterna ultravioleta = with the ultraviolet flashlight
• more naturally in English: using the ultraviolet flashlight

Spanish often uses con to show the instrument or tool used to do something:

• Escribo con un bolígrafo. = I write with a pen.
• Abrió la puerta con una llave. = He opened the door with a key.
• Buscamos otro indicio con la linterna ultravioleta. = We look for / are looking for another clue using the UV flashlight.

Using la suggests the flashlight is already known in the context.

So la linterna ultravioleta means:

• the ultraviolet flashlight

This often happens when the speaker and listener both know which object is meant, or when it has already been mentioned.

If it were not known or not specific, Spanish could say:

• con una linterna ultravioleta = with an ultraviolet flashlight

So the choice between la and una depends on context, just like the versus a/an in English.

Yes. In linterna ultravioleta, ultravioleta describes the type of flashlight.

So:

• linterna = flashlight
• ultravioleta = ultraviolet / UV

Together:

• linterna ultravioleta = ultraviolet flashlight or UV flashlight

This is a normal noun + adjective structure in Spanish:

• luz natural
• cámara digital
• linterna ultravioleta

It does agree in the way Spanish normally allows for this adjective.

Ultravioleta has the same form for masculine and feminine singular:

• un foco ultravioleta
• una linterna ultravioleta

In the plural, you will often see:

• rayos ultravioletas
• luces ultravioletas

So in this sentence, ultravioleta is perfectly correct with linterna, which is feminine singular.

In theory, a prepositional phrase can sometimes create ambiguity, but here the natural interpretation is that we are using the flashlight to search.

So the sentence is understood as:

• We are looking for another clue with the UV flashlight

Not:

• We are looking for another clue that has a UV flashlight

That second idea would make little sense in context, so native speakers automatically understand con la linterna ultravioleta as describing how the searching is being done.

Yes, both patterns are possible, but they are slightly different in style.

• linterna ultravioleta is a compact, natural way to say UV flashlight
• linterna de luz ultravioleta is more explicit: flashlight with ultraviolet light

Spanish often uses a noun + adjective structure where English might also use a compound noun:

• luz artificial
• radiación solar
• linterna ultravioleta

So the sentence’s version is concise and idiomatic.

Yes. Spanish word order is more flexible than English word order.

These are both natural:

• Buscamos otro indicio con la linterna ultravioleta.
• Con la linterna ultravioleta buscamos otro indicio.

The second version puts more focus on how the search is being done. The first is the more neutral order.

So changing the order usually changes emphasis, not the basic meaning.

Because the personal a is mainly used with direct objects that are specific people, and sometimes pets or personified beings.

Here, otro indicio is a thing, not a person, so no a is used:

• Buscamos otro indicio.

Compare:

• Buscamos a María. = We’re looking for María.
• Buscamos otro indicio. = We’re looking for another clue.

That difference is very important in Spanish.