じしゅ自首jishu
1.

The act of voluntarily reporting oneself to law enforcement authorities after committing a crime, often before any investigation has revealed the crime or the perpetrator's identity.

2.

A legal procedure where an offender comes forward to confess their crime, typically seeking leniency in their sentencing as a result of their proactive admission of guilt.

3.

The act of self-surrender by an individual who has violated the law, involving a formal declaration of wrongdoing to the relevant investigative bodies.

Example:

その犯人は警察に自首した。