George Doby had been married to his wife 57 years on the day authorities say he shot and killed her and their 12-year-old grandson before killing himself.

Two of the couple's children and four of their grandchildren had come to George and Edna Doby's house south of Atlanta on Sunday afternoon to celebrate their anniversary, according to a police report released Monday.

"This was an all-American family," said East Point police Capt. Russell Popham. "The family's still struggling to understand why he did it and obviously we'll never know now."

He said the Dobys were a close-knit family that often got together for Sunday dinner. Family members told police that George Doby did not appear upset or agitated Sunday before the shooting.

The couple's daughter, Jane Laughridge, told authorities she was in the kitchen making dinner with her daughter Sunday afternoon and could see her parents standing next to each other in the backyard.

Laughridge said she looked away and then several gunshots rang out. When she looked back, her parents and nephew were lying in the yard, according to the report.

Laughridge's brother, Alan Doby, said he was in the basement with two of his children when he heard the shots. He said he raced up the stairs and into the backyard where his parents and 12-year-old son lay, all shot in the chest. George Doby, the family patriarch, had a Colt .45-caliber revolver in his hand, police said.

Authorities said Alan Doby shouted to his sister to call 911 and started performing CPR on his son. A neighbor, Glenn Bowman, also heard the shots and called police, authorities said.

East Point Police on Monday were still searching for a motive in the killings. Efforts to reach members of the Doby family were unsuccessful. A man who answered the phone at a Doby residence declined comment.

Bowman told The Atlanta Journal-Constitution that George Doby, 87, had failing eyesight. His wife, Moiselle "Edna" Doby, 82, had been diagnosed with Parkinson's Disease.

Edna Doby and her grandson — who was autistic — were shot multiple times. George Doby had a single, self-inflicted wound.