A second man is facing charges in connection with a late morning fatal shooting of a 23-year-old man last month inside an apartment on Lyndhurst Street in Dorchester. Reginald Holley, 22, was arrested Monday and charged with murder, armed robbery, and unlawful possession of a firearm, police and prosecutors said. Another man, Oasis Pritchett, 22, is facing identical charges in the slaying of Alfonso Rivas. Rivas was gunned down Oct. 17 at about 11:05 a.m., while his girlfriend and children were in an adjoining apartment, authorities said.Travis Andersen can be reached at firstname.lastname@example.org. Follow him on Twitter @TAGlobe.