From Sahih Bukhari (Hadith 2290):
Narrated Muhammad bin 'Amr Al-Aslami that his father Hamza said:'Umar (ra) sent him (i.e. Hamza) as a Sadaqa / Zakat collector. A man had committed illegal sexual intercourse with the slave girl of his wife. Hamza took (personal) sureties for the adulterer till they came to 'Umar. 'Umar had lashed the adulterer one hundred lashes. 'Umar confirmed their claim (that the adulterer had already been punished) and excused him because of being Ignorant. Jarir Al-Ash'ath said to Ibn Mas'ud regarding renegades (i.e., those who became infidels after embracing Islam), "Let them repent and take (personal) sureties for them." They repented and their relatives stood sureties for them. According to Hammad, if somebody stands surety for another person and that person dies, the person giving surety will be released from responsibility. According to Al-Hakam, his responsibilities continues
Reference: Bukhari 2290