Miller, 19, is described as a white woman, 5 feet 4 inches tall, 125 pounds, brown hair, blue eyes. She sometimes goes by the names Kia, Keisha and Kesha, Harsh said.
Miller's alleged companion at the time of the crime was arrested under the name "James Thomas," 30, of 44 1/2 E. Franklin St.
Harsh said the investigation has revealed his name is Thomas Clifford Wallace, age 30 or 31.
He was in jail on a drug charge when he was charged with attempted murder in the beating of Darrius Allen Fetterhoff of Greencastle, Pa.
After Fetterhoff died on Aug. 28, authorities petitioned the Washington County Grand Jury for a murder indictment. That indictment was handed up in October, Harsh said.
Miller was indicted at a later grand jury session.
Fetterhoff, 58, who was struck in the head and rolled over a 90-foot embankment, was left for dead on Aug. 20, police said.
Fetterhoff apparently remained along the Conococheague Creek east of the Creek Bridge on Broadfording Road for nearly a week after the beating.
Crime Solvers is seeking the help of the community.
Anyone with information may call Harsh at 301-791-3020 or 301-791-3300, ext. 117.