Post: Accused trooper killer previously charged with attempted murder of police officer; case dropped

Parolee, pal held in Md. state trooper's killing,
Post, 15 Jun 2010 (Zapotosky & Castaneda)

... In 2006, Williams also was charged with attempted murder for apparently firing a gun at a police officer on New Year's Day. A witness who knew Williams identified him as the attacker from a photo array, but on the day the case was to go to trial, the state dropped the charges when its witness did not appear in court, according to prosecutors and Douglas J. Wood, Williams's attorney in the case....