SERIAL KILLER: The man Prince George’s police say was a serial killer who committed two mother-daughter slayings had a long criminal past. He was arrested last year for selling firearms from a parking lot, sources and court documents say.

OFFICERS: The number of law enforcement officers killed on duty is surging, both locally and nationwide. More Maryland officers have been killed so far this year than in all of 2009.

SEX CRIMES: Sexual assaults in D.C. are up nearly 50 percent for the first five months of 2010.

TERRORIST: A Northern Virginia man is accused of providing aid to the Somali terrorist organization al-Shabaab.