The police haven't caught the culprit yet.
犯人は現場に指紋を残していた。
The offender left fingerprints at the scene.
The police went into the mountains chasing the culprit.
The culprit fled the scene by car.
A week later, the culprit was finally caught.
The investigation revealed that she was the culprit.
犯人 means 'the criminal' (the person), while 犯罪 means 'the crime' (the act), and learners often mix up the two due to the shared kanji 犯.
heinous criminal; vicious criminal
arsonist