criminal case
Refers to a legal case involving a crime, as opposed to a civil case (民事事件). Common in news and legal contexts.
彼は刑事事件の弁護を専門にしている。
He specializes in defending criminal cases.
That case will likely be treated as a criminal case.
That violent incident developed into a criminal case.
The police built this fraud into a criminal case.
The company's fraudulent accounting escalated into a criminal case.