Incriminar vs. armar
While both words relate to establishing guilt, incriminar acts as a formal term describing the connection between a person and a crime through evidence. In contrast, armar is a colloquial term that describes the active plotting, setup, or conspiracy to trick someone or make them look guilty when they are not.
Incriminar
B2This is a formal verb that means to accuse someone of a crime or to provide evidence that suggests someone is guilty. It focuses on the result of the evidence pointing toward a suspect. It can be used whether the person is actually guilty or if the evidence was faked to frame them.
O advogado disse que as novas provas vão incriminar o verdadeiro culpado.
(The lawyer said the new evidence will incriminate the real culprit.)
Ele tentou incriminar o colega colocando o dinheiro roubado na mesa dele.
(He tried to frame his colleague by putting the stolen money on his desk.)
Não diga nada que possa te incriminar no tribunal.
(Do not say anything that could incriminate you in court.)
A polícia encontrou digitais que serviram para incriminar o suspeito.
(The police found fingerprints that served to incriminate the suspect.)
Armar
B1In the context of framing someone, armar (often used with para, contra, or as armar uma cilada) refers to the act of setting a trap or organizing a scheme. It implies a malicious intent to create a situation where an innocent person takes the fall. It corresponds closely to setting someone up.
Eu não fiz nada, eles armaram para mim!
(I didn't do anything, they framed me!)
Tenho certeza de que estão tentando armar uma cilada para o prefeito.
(I am sure they are trying to set a trap for the mayor.)
O chefe armou para que o funcionário parecesse incompetente.
(The boss set it up so the employee would look incompetent.)
Vocês armaram tudo isso só para me prejudicar.
(You all set this whole thing up just to harm me.)
Summary
Use incriminar when discussing the legal or factual link between a person and a crime, focusing on accusation or evidence. Use armar when discussing the scheme, plot, or trap used to deceive others and make an innocent person appear guilty.