Sulayman al-Muzani said: I asked Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) for a ruling about a man who beat his slave and he died, though he had not intended to kill him. Sayyiduna Ibn Abbas (may Allah be pleased with him) said: He should (in compensation) free a slave, or fast for two consecutive months.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنايات / 15955