"I don't think there'd be gentrification if they were still at 500 homicides," O'Malley said. He believes Baltimore is "three, four, maybe five years behind D.C." in crime declines.
Batts attributed the increase in violence to warring gangs, saying that the prison-based Black Guerrilla Family was extorting other gangs, leading to a turf war between the BGF and the Bloods. But it was unclear how many shootings were gang-related — police often say publicly that they know of no motive for the attacks — and most remain unsolved.
The Police Department made arrests in several high-profile cases in 2012. Those included the disappearance of Phylicia Barnes, whose sister's ex-boyfriend was charged with murder in the North Carolina teen's death; the killing of 12-year-old Sean Johnson in 2011; and charges in a series of retaliatory shootings in East Baltimore, an investigation coordinated by a new major crimes unit in the state's attorney's office.
But city homicide investigators continue to struggle to close cases. And in some instances, police and prosecutors continue to clash behind the scenes, with prosecutors exerting greater oversight over when charges can be brought.
Among the year's unsolved cases is the stabbing death of 84-year-old Mary Hines, whose East Baltimore home was set on fire with her body inside.
Col. Garnell Green, who has led the homicide unit for the past year and will be moving to oversee the patrol division, said Hines' death was "deeply troubling to us all."
"Detectives have solved many of [2012's] murders and continue to make good progress," Green said. "However, in the case of Mary Hines, we are continuing to ask for the public's help. Someone out there knows what happened. ... We have some good leads, but we still need the public's help."
Other unsolved cases include those of Alonzo Gladden, 24, a sailor visiting family in South Baltimore while on leave from the Navy; Peter Marvit, a researcher for the National Institutes of Health shot in front of his Northeast Baltimore home; and 22-year-old Larelle Amos, who was killed outside a Northeast Baltimore party by a stray bullet. Police ask anyone with information on these or other killings to call 410-396-2100.
Batts announced last week a major reshuffling of the department's leadership positions — moves designed to focus on community outreach and intelligence-gathering. He has emphasized foot patrols, and the agency has started a partnership with state troopers in high-crime areas on weekends.
O'Malley said federal, state, and local law enforcement agencies are working together more and have never been better aligned.
"It would be nice if there were steady and mathematically predictable progress all the time, but sometimes that's not the way the real world works," O'Malley said of Baltimore year's in crime. "I'm hopeful that the new commissioner, after this long period of transition, will be able to restore the focus to violent crime reduction."
Baltimore Sun reporter Luke Broadwater contributed to this article