it is not for a believer to slay another believer unless by mistake. and he who has slain a believer by mistake his atonement is to set free from bondage a believing person and to pay bloodmoney to his heirs unless they forgo it by way of charity. and if the slain belonged to a hostile people but was a believer then the atonement is to set free from bondage a believing person. and if the slain belonged to a people with whom you have a covenant then the atonement is to pay the bloodmoney to his heirs and to set free from bondage a believing person. but he who cannot should fast for two consecutive months. this is the penance ordained by allah. allah is allknowing allwise.
وما كان لمؤمن أن يقتل مؤمنا إلا خطأ ومن قتل مؤمنا خطأ فتحرير رقبة مؤمنة ودية مسلمة إلى أهله إلا أن يصدقوا فإن كان من قوم عدو لكم وهو مؤمن فتحرير رقبة مؤمنة وإن كان من قوم بينكم وبينهم ميثاق فدية مسلمة إلى أهله وتحرير رقبة مؤمنة فمن لم يجد فصيام شهرين متتابعين توبة من الله وكان الله عليما حكيما