A Fine Resource to Better Understand Honor Killings among Muslims is the "Honor Killings Index" at Wikiislam.

This Index, which can be found at this link, provides readers with brief accounts of individual honor killings, including the age & name of victim (if available), the relationship of the killer to the victim, when & where the killing took place, and the reasons the murderers wanted the victims dead. 
In looking at all the cases, we note that almost all the murderers are men, and almost all the victims are young women.