It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Help your brother, whether he is a wrongdoer or wronged." He said: O Messenger of Allah, we can certainly help the one who is wronged, but how shall we help the wrongdoer? He (peace and blessings be upon him) said: "By seizing him (restraining him from wrongdoing)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الغصب / 11510