A person who has committed theft; a thief — a somewhat legal or journalistic term for a robber.
防犯カメラが窃盗犯を捉えていた。
The security camera captured the thief.
警察は近くで目撃情報のあった窃盗犯を追っている。
The police are pursuing the thief who was sighted nearby.
窃盗犯は現行犯で逮捕された。
The thief was arrested in the act.