D.C. police on Wednesday announced arrests in four unrelated homicides in the District that took place between October 2007 and June 2012.

On Wednesday, police arrested Steven Vondell Williams, 46, of Northwest Washington, charging him with second-degree murder while armed in the death of a Rockville woman at her store in the 700 block of H Street NE. Hae Soon Lim, 64, who was known as “June” in the neighborhood, was found fatally shot shortly after 6 a.m. June 14 inside the Grace Deli.

Williams was arrested in August on a warrant in connection with a Virginia parole violation. At the time, police had already been notified that DNA found on a holster recovered during the D.C. homicide probe belonged to him, according to court documents.

“Forensic evidence was extremely important in this case,” D.C. Police Chief Cathy L. Lanier said during an afternoon news conference. She declined to provide specifics of the investigation.

Police said Williams was brought to the District, where he was charged with Lim’s murder. Officials declined to discuss the prior arrest or his record.

“H Street is one of the fastest-developing areas of the city,” Lanier said. “They were devastated when they heard about this case. I know this will bring a lot of relief to the community and the family.”

The other arrests announced Wednesday were related to homicides from this year, April 2011 and 2007.

Police said they arrested David Tyrone Robinson, 20, of Northeast, on Tuesday, charging him with second-degree murder while armed in the death of Howard Ricardo Sampler, 21.

Sampler, of Southeast, was found suffering from multiple gunshot wounds just before 6 p.m. Jan. 3 in the 1500 block of 45th Street NE. He was taken to a hospital, where he died. His death marked the District’s second homicide of the year. Lanier said Wednesday that the city has recorded 78 homicides in 2012.

In another case, Dennis Washington, 42, of Southeast, was arrested Wednesday, according to police, and charged with second-degree murder in the death of Thomas Glenn Lipscomb, 49.

Lipscomb, of Southeast, was found dead in an apartment in the 3500 block of Minnesota Avenue SE about noon April 26, 2011. After an autopsy, police said, his death was ruled a homicide caused by blunt force trauma.

Police said they arrested two men Tuesday in connection with the Oct. 29, 2007, shooting death of Michael Antonio Pearson, 27, in the 2100 block of I Street Northeast. They charged Charles Mason, 21, and Jekwon Smith, 21, both of Northeast, with first-degree murder while armed.