Witnesses said Robert L. Clark Jr. shot his wife and grandson at his home, then turned his pistol on officers during a family dispute over a watermelon, Commerce police Chief John Gaissert said.
Officers shot Clark when he came to the door with gun in hand, Gaissert said.
"At this point, we believe that it was a dispute over a watermelon that precipitated the argument that escalated into this deadly situation," Gaissert said.
Clark became enraged after one of his grandsons had either dropped a watermelon or taken a piece of watermelon without asking, he said.
Clark, of 228 Troy St., faces charges of murder, aggravated assault and aggravated assault on a police officer.
He was being held Monday in a secure room at Atlanta Medical Center, where he is being treated for gunshot wounds, Gaissert said.
His wife, Linda Clark, 58, remains in stable condition at Grady Memorial Hospital with a single gunshot wound, he said.
Police responding to a 911 call shortly before 1 p.m. were greeted with a gunshot through the front door of the house, which is off Georgia Highway 15 Alternate, just north of downtown Commerce.
The shot touched off a 20-minute standoff. Officers reached Clark by telephone after they heard a second gunshot, and he allowed his wounded wife and their 5-year-old grandson to leave through the back door, according to the Clarks' neighbors and police.
Clark then opened the front door armed with a pistol. Officers shot him, and inside found the body of 6-year-old Michael Levigne, who had died from a gunshot wound.
GBI agents blocked off Troy Street on Monday as they scoured the home for evidence.
Some neighbors, hitting a deadend of crime scene tape, sat in their cars for a few moments watching investigators map the location of bullet holes in the front of the house before turning around and driving away.
About six shots were fired altogether, said neighbor Kathy Baker, who got on her kitchen floor when she saw police outside of her window with guns drawn.
GBI agents are investigating the police response while also assisting Commerce police with the assault and homicide investigations, said Jim Fullington, special agent in charge of the GBI's Athens office. Two Commerce police officers were placed on paid leave, but there is no indication they did anything wrong, Fullington said.
The Clarks have a history of heated domestic disputes, Gaissert said.
Police have been sent to the house half a dozen times in the past year to answer 911 calls or 911 hang-ups, he said.
Michael, who had just finished kindergarten at Commerce Primary School, and his younger brother were in their maternal grandparents' custody for at least three years, according to police and a neighbor.
Their father, Andrew Levigne, has been arrested repeatedly by Commerce police, and authorities cannot find their mother, Gaissert said.
The Jackson County Department of Family and Children Services is investigating whether the boys should have been left in the care of their grandparents, but there were no red flags to indicate they were being abused or neglected, Gaissert said.
Michael was always at school, and teachers never had any problems dealing with his grandparents, said Kim Savage, the principal at Commerce Primary School.
"Miss Linda is such a sweet person," Savage said. "She always made sure they were at school and that they had everything they needed."
Michael's younger brother is staying at a neighbor's home until DFACS personnel can find a foster home for him.