Probability in the past (terá sido)

The future perfect for past probability

In a previous lesson, you learned how to use the future perfect (Futuro Composto do Indicativo) to describe actions completed by a future deadline. However, this tense has another very common—and very useful—function in Portuguese: expressing a guess, probability, or supposition about something that already happened.

When piecing together a mystery, investigating a crime, or simply gossiping, you will frequently use this tense to describe what must have happened or what probably occurred.

The structure is exactly the same as before: the future tense of the auxiliary verb ter + the past participle of your main verb.

They say that the inspector must have arrived late to the scene.
Dizem que o inspetor terá chegado atrasado à cena.
Someone must have left the footprint in the mud.
Alguém terá deixado a pegada na lama.
The thief must have had an accomplice in the bank.
O ladrão terá tido um cúmplice no banco.

Asking questions and expressing doubt

When you ask a question using this tense, it expresses doubt, wonder, or speculation. In English, this translates roughly to "Could [someone] have [done]...?" or "I wonder if...".

Could the inspector have discovered the truth?
O inspetor terá descoberto a verdade?
Could the witness have invented the false alibi?
A testemunha terá inventado o álibi falso?
Who could have tried to kidnap the girl?
Quem terá tentado raptar a menina?

Negative suppositions

When you use this tense in a negative sentence, you are guessing that an event most likely did not occur. This translates to "probably didn't" or "must not have".

the alibi
o álibi
The suspect probably did not have a good alibi.
O suspeito não terá tido um bom álibi.
They probably did not find any trace of blood on the rug.
Não terão encontrado nenhum vestígio de sangue no tapete.