Dan karısını öldürdü ve bunu bilinmeyen bir saldırganın işi olarak gösterdi. - Dan killed his wife and made it appear as the work of an unknown assailant.
Saldırgan bir maske takıyordu. - The assailant was wearing a mask.
Someone's assailant is a person who has physically attacked them. Other party-goers rescued the injured man from his assailant. = attacker. someone who attacks another person = attacker