KNOXVILLE, Tenn. (AP) _ The maternal grandfather of a 10-year-old boy at the center of a custody dispute fatally shot the boy's paternal grandparents during an argument after watching him play baseball, authorities said Wednesday.

The shooting occurred Monday night as about 75 adults and children made their way to the parking lot at a baseball field nicknamed Field of Dreams in Dandridge, a lakeside community overlooking the Great Smoky Mountains about 30 miles east of Knoxville.

Three members of the boy's family were killed.

District Attorney General Jimmy Dunn told The Associated Press that the boy's father, Jerry B. ``Brent'' Shands and at least two other men ran over to try and stop his former father-in-law, Samuel L. Noe. They wrestled for the gun ``and at some point during the struggle the gun went off at least one time, maybe twice,'' wounding Shands and killing Noe, the prosecutor said.

Asked if there was anyone to charge, Dunn said, ``It doesn't appear to be.''

Ten-year-old Austin Shands was uninjured but dazed, witnesses said. No one else was hurt. The child was being taken care of by friends, said his uncle, Bobby Shands.

Fraternal grandfather Jerry D. Shands, 63, and Noe, 61, died instantly. Fraternal grandmother Ellen E. ``Sue'' Shands, 62, was dead on arrival at a local hospital. The boy's father was flown to University of Tennessee Medical Center in Knoxville, where his family said he was in serious condition. All were from the Jefferson City area.

Family members have said the dispute stemmed from the bitter divorce of Austin's parents and their court fight over the boy's custody.

The boy's mother, Diane Shands Robbins, was arrested in a drug raid in April 2005. On Sept. 13, she pleaded guilty to a federal charge of conspiring to distribute marijuana. She was remanded to the federal prison system while awaiting sentencing Dec. 1, court records show.

Her mother, Patricia Noe, who also attended the game, may have sparked the confrontation when she said something to Jerry Shands and pointed an umbrella at him, the district attorney said.

``Then, of course, he says, 'Get that blankety-blank thing out of my face.' ... And the next thing you hear is pop, pop, pop (from Samuel Noe's gun).''