For the more wonkish among you, here is the research data that the USA Today article below is based on.
http://pediatrics.aappublications.org/cgi/content/abstract/124/2/e210
Published online July 20, 2009
PEDIATRICS Vol. 124 No. 2 August 2009, pp. e210-e217
(doi:10.1542/peds.2008-3675)
ARTICLE
Characteristics of Infant Homicides: Findings From a U.S. Multisite Reporting System
Takeo Fujiwara, MD, PhD, MPHa,b, Catherine Barber, MPAa, Judy Schaechter, MDc and David Hemenway, PhDa
a Harvard Injury Control Research Center, Harvard School of Public Health, Boston, Massachusetts
b Department of Health Promotion, National Institute of Public Health, Saitama, Japan
c Department of Pediatrics, Miller School of Medicine, University of Miami, Miami, Florida
OBJECTIVE: The purpose of this study was to describe homicides of infants (children under 2 years of age) in the US. Seventy-five percent of the incidents were type 1 incidents, perpetrated mainly by men (83%; typically the infant's father or the boyfriend of the infant's mother). In 85% of the type 1 incidents, the infant was transported to the hospital, usually at the initiative of the perpetrator or another household member. In almost one half of the type 1 incidents, a false story was offered initially to explain the injuries. In contrast, the type 2 incidents (16 cases) were perpetrated mainly by women (11 of 16 cases) and involved methods such as poisoning, drowning, sharp instruments, or withdrawal of food and water; most infants were not taken to the hospital. Although 93% of incidents were perpetrated by caretakers, the large differences between the 2 incident types suggest different avenues for prevention.
CONCLUSIONS: The circumstances involved in the type 1 homicides (beatings by caretakers) suggested that those attacks occurred impulsively, death was unintended, and emergency care was summoned, often with a false story. Previous abuse was suspected in more than one half of those incidents.