In a 15-month study, The Post individually tracked every homicide in the District between 2000 and 2011 to learn what ultimately happened to each ensuing case. Such studies, known as longitudinal, are not generally produced by law enforcement, because they are considered to be too time-consuming.
The study found that out of 2,294 homicides in the period, 30 percent have led to a conviction for murder or manslaughter, according to the analysis of police and court records. The Post last published a similar study in 1993, when it found that 25 percent of the 1,286 homicides between 1988 and 1990 led to such a conviction.
The latest study shows that from 2000 through 2006, under Police Chief Charles H. Ramsey, the number rose to 29 percent for the 1,544 homicides over that period.
The trend has continued to improve in recent years for the 750 homicides under Cathy L. Lanier — to 35 percent between 2007 and 2009 — and analysis indicates it will continue to rise in subsequent years as pending cases are adjudicated.
The study shows that even as homicide trends improve — as caseloads lessen and police pursue innovative crime strategies — a hard residue remains of killings that are difficult to solve and prosecute, mainly involving drugs or retaliation.
“This is a good-news, less-good-news story,” said Richard Rosenfeld, a criminology professor at the University of Missouri at St. Louis. “The good news is that there’s a drop in homicides in the District of Columbia and the United States. What does that mean? What D.C. and other cities are faced with is a different mix of cases that end in homicide, and those cases are tough to prosecute.”
U.S. Attorney Ronald C. Machen said the Post study is “not necessarily a reflection” of how well his office is prosecuting homicides.
“What you’re really measuring in my view is, okay, a person is killed on the street: What is the likelihood that person would get convicted at the end of the day? That’s different than conviction rate,” he said. “What you’re measuring, to me, is more a reflection of, is the community coming forward and giving you enough information to make an arrest? If you never have enough information to even arrest somebody, you can’t hold them accountable for those murders.”
He said that cooperation from the community has improved in recent years but that historically it has been a problem.
“It used to be, when I was in this office before, people would rather talk to anybody than a prosecutor or police officer,” said Machen, who worked as an assistant U.S. attorney in D.C. from 1997 to 2001, including a year in the homicide section. “We would have people whose family members have been killed and they would not talk to us about the murder.”