Authorities in South Carolina say a man shot and killed his wife, her son and his girlfriend before he turned the gun on himself.

York County Sheriff's Office spokesman Trent Faris told a brief news conference Tuesday that he couldn't say what motivated 55-year-old Randy Moore to shoot his wife, 50-year-old Assistant York County Manager Anna Hubbard Moore; her 31-year-old son, Jason Lockamy of Hamlet, North Carolina; and his 31-year-old girlfriend, Lora Kathryn Young of Fairmont, North Carolina.

Faris said investigators are working as quickly as possible to get answers for the families of the victims. He said investigators also are awaiting results from a ballistics test and other forensic tests.

Neighbors said the Moores had just moved to the home where the shootings occurred Sunday.