Dwayne Moore, 33, has been charged with four counts of murder in connection with the Sept. 28th shooting deaths of three adults and a 2-year-old child at a home in Boston's Mattapan neighborhood.
The victims were found in various states of undress and had been shot several times.
A fourth adult was critically injured in the incident.
Suffolk County District Attorney Daniel F. Conley declined to comment on Moore's arrest because the investigation is ongoing.
Police said Moore has a criminal record and was recently released after spending several years in state prison.
Police suspect a drug connection to the killings.