The Department of Children and Families has said it investigated the family of 41-year-old Daryl Benway 10 years ago.
Benway's body was found with his daughter's in their Oxford home on Saturday. The man's son was found shot in the head and was taken to UMass Memorial Children's Medical Center where he remained in critical condition.
Benway's wife returned home after the shootings, unaware of what had happened.
DCF officials said they had investigated the family from 2002 to 2003 after receiving reports of abuse and neglect on behalf of an older child in the family. Officials would not offer any further details about the investigation and did not say if the child involved in the investigation was Benway's son.
A vigil was held at 7:30 p.m. Monday on Main Street in Oxford's town center, Oxford schools superintendent Allen Himmelberger said.
Schools officials are offering grief counseling to community members Tuesday at A.M. Chaffee Elementary School, where 7-year-old Abigail Benway was to start second grade next month.