It was 1:44 p.m. local time.
His grandparents could barely hear the 14-year-old because of his crying, CNN affiliate WYFF reported. So they headed next door, where he lived, to check on him.
But instead of the teen, the grandparents found the body of their son -- his father. Their grandson was nowhere to be found, according to the affiliate.
At about 1:45 p.m., a teacher called 911 to report a shooting at the playground behind nearby Townville Elementary School.
The teen allegedly drove a Dodge Ram onto school property and jumped a fence to access the playground, according to CNN affiliate WNHS. It said he never entered the school.
By the time the gunfire stopped, he'd wounded two students and a teacher, authorities say.
The teen, who was not identified because he is a minor, was taken down by a volunteer firefighter and detained by deputies.
3 wounded, father dead
The father, who was identified as Jeffrey Osborne, 47, suffered gunshot wounds, Anderson County Coroner Greg Shore said.
Away from the home, at the elementary school 2 miles away, one male student was critically injured with a gunshot to the leg and another boy was struck in the foot. A female teacher was wounded in the shoulder, sheriff's Capt. Garland Major said.
The teacher and one student were treated at a local health center and released Wednesday evening, hospital spokesman Ross Norton told CNN. A third victim was transported to a hospital in critical condition, officials said.
'There was a bunch of kids crying'.
The boy started firing after getting out of his vehicle, Anderson County Sheriff John Skipper said.
It appeared he was headed toward the school, but teachers locked doors to prevent him from getting in, police said.
Jamie Meredith, the mother of a student at the school, told WYFF that her daughter and classmates hid in a bathroom.
"I don't know how they knew to go in the bathroom, but I know her teacher was shaken up. I know all the kids were scared. There was a bunch of kids crying. She didn't talk for about five minutes when I got her."
It is unclear whether the alleged shooter knew any of the school victims. While his motive is unclear, terrorism has been ruled out, authorities say. CNN has not determined whether the suspect has an attorney.
Veteran firefighter helped save lives
School nurses and emergency responders saved the life of the boy who was shot in the leg, said Scott Stoller, the director of EMS in Anderson County.
"Training, proper equipment is absolutely critical and without their early intervention the outcome would have been very different," he said.
One of the people credited with saving lives is firefighter Jamie Brock, who declined to talk to the media. The 30-year veteran volunteer firefighter, who was not armed, took down the suspect on the playground, the affiliate reported.
Active shooter training
The school has no video cameras, according to Joanne Avery, superintendent for Anderson County District 4. She told WYFF that the staff has had a lot of active shooter training, which came in handy during the incident.
"We are heartbroken about this senseless act of violence," Avery said
Townville Elementary has canceled classes for the rest of the week, and is providing counseling services.
The school is southwest of Greenville -- near the Georgia line -- and has about 280 students and 30 school employees, according to its website.