In the Amagasaki Serial Murder Incident (尼崎連続殺人事件), several family households were tortured continuously for more than 25 years. These crimes were committed mainly in Amagasaki, and also in six prefectures, Hyogo, Kochi, Kagawa, Okayama, Shiga and Kyoto. Many people were abused and imprisoned; at least 8 people were killed.
The incident was discovered when the suspects Miyoko Sumida (角田美代子) and Masanori Sumida (角田正則) were arrested in November 2011.
References
Amagasaki Serial Murder Incident Wikipedia(Text) CC BY-SA