Who is murdering the kids? (Arizona)

Excerpt from Arizona's recently released 2011 Child Fatality review:

http://www.havasunews.com/news/arizona-s-child-fatality-review-report-lists-deaths/article_de90399a-3210-11e2-9c6d-0019bb2963f4.html

There were 42 children who were victims of homicide in 2011, compared to 36 in 2010. Blunt force trauma (52 percent) was the leading cause of death, followed by firearm injuries (29 percent). The perpetrator was the child’s biological father in 36 percent of the 2011 incidents. Seventeen percent of cases were the perpetrators relationship to the child was undetermined. In descending order of percentage, other cases include the mother’s partners, a friend of the child’s, strangers, other relative, gang members, child’s boyfriend or girlfriend, biological mother, and step-parent.