The Messenger of Allah ﷺ said, "Whoever kills a believer deliberately is to be handed over to the family of the slain. If they wish, they may put him to death, and if they wish, they may accept the blood-money, which consists of thirty four-year-old she-camels, thirty five-year-old she-camels, and forty pregnant she-camels. Whatever they settle upon belongs to them. This is to make the blood-money heavier."
حدثنا أحمد بن سعيد الدارمي أخبرنا حبان وهو ابن هلال حدثنا محمد بن راشد أخبرنا سليمان بن موسى
أن رسول الله ﷺ قال من قتل مؤمنا متعمدا دفع إلى أولياء المقتول فإن شاءوا قتلوا وإن شاءوا أخذوا الدية وهي ثلاثون حقة وثلاثون جذعة وأربعون خلفة وما صالحوا عليه فهو لهم وذلك لتشديد العقل
[Its chain of transmission is hasan] Ibn Majah also reported it in the Book of Diyat, Chapter on the diyah for unintentional killing, hadith no. 2629, from Muhammad bin Bashar through the same chain, and Nasai graded it daif.