The US Marshals Service said a Pennsylvania man arrested on Friday in Vermont is awaiting extradition back to Philadelphia to face charges of murder and sexual assault on a minor. Authorities say Clifford ‘‘Murdah’’ Moore was arrested in a cab headed to Burlington International Airport. Moore, 34, was awaiting trial in Philadelphia after being charged with murder in 2010. While out on bail, he was charged with unlawful contact with a minor, statutory sexual assault, intimidation of a witness, corruption of a minor, and making terrorist threats. Authorities said Moore failed to appear for his trial, and a warrant was issued for him in November.