Investigação vs. inquérito
While both investigação and inquérito relate to solving crimes, they function differently within the legal and police systems. Generally, investigação refers to the broader act of gathering evidence and researching facts, whereas inquérito refers to the specific, formal administrative procedure or the official case file opened by authorities.
Investigação
B1This word describes the general action or process of investigating. It focuses on the detective work, intelligence gathering, and the active search for clues. Investigação is a broader term that can be used by the police, private detectives, or journalists. It describes what the authorities are doing (the activity) rather than the formal bureaucratic procedure.
A investigação revelou que o suspeito estava fora do país.
(The investigation revealed that the suspect was out of the country.)
Os detetives continuam a investigação sobre o desaparecimento.
(The detectives continue the investigation into the disappearance.)
Jornalistas fizeram uma investigação independente sobre a corrupção.
(Journalists conducted an independent investigation into the corruption.)
Essa investigação requer muita paciência e análise de dados.
(This investigation requires a lot of patience and data analysis.)
O sucesso da investigação depende da cooperação das testemunhas.
(The success of the investigation depends on the cooperation of the witnesses.)
Inquérito
C1This term refers to the formal, official legal inquiry or investigation file. In criminal contexts, it is often called inquérito policial (police inquiry). It is a bureaucratic instrument: it is opened (aberto), conducted (conduzido), and eventually closed (arquivado) or sent to a judge. While investigação is the work being done, inquérito is the official folder or procedure containing that work.
O delegado decidiu abrir um inquérito para apurar o crime.
(The police chief decided to open an investigation to clarify the crime.)
O inquérito foi arquivado por falta de provas concretas.
(The investigation was closed due to lack of concrete evidence.)
O advogado pediu acesso aos autos do inquérito policial.
(The lawyer requested access to the police investigation files.)
Após a conclusão do inquérito, o caso foi enviado ao juiz.
(After the investigation was completed, the case was sent to the judge.)
Este inquérito corre em segredo de justiça.
(This investigation is subject to judicial secrecy.)
Summary
To summarize, use investigação when discussing the active work of looking for clues, researching, and solving the mystery. Use inquérito when discussing the formal legal procedure, the official paperwork, or the specific case file opened by the police or prosecutor. Essentially, an investigação happens inside an inquérito.