COLUMBUS (AP) - Knowing someone had fired a shot into Hamilton Central Elementary, parents watched nervously in the school gym as their kids dribbled basketballs around orange cones.

They said they didn't want to change their plans despite news Tuesday that authorities had linked the school shooting with 11 others along a five-mile stretch of interstate, including one that killed a woman.

Greg Mellon said he hoped shooting baskets at the recreation league practice would calm the kids, including his 8-year-old son Corbin, who was so frightened he cowered under the dashboard on the way to practice.

''He ducked down in the car,'' Mellon said. ''Of course he's worried about it.

Four of the shootings - three at vehicles and one at the school last month - were from the same gun, Franklin County Sheriff's Chief Deputy Steve Martin said Tuesday.

Although ballistics tests could not link the rest of the shootings along Interstate 270, investigators said they ''are comfortable'' saying all 12 are connected, he said. He would not elaborate.

Authorities have received more than 500 tips, but would not speculate about who the shooter might be and would not release the type of weapon.

''We think it's not good for us to put that information out,'' Martin said. ''We don't want people to stop calling us because we put out that kind of information.''

Martin said investigators are not relying on a profile of a suspect and are exploring all possibilities.

Local businesses have established a $10,000 reward for information leading to an arrest.

The shootings began in May along Interstate 270, the freeway that circles Columbus. Many were not reported until after Nov. 25, when 62-year-old Gail Knisley of Washington Court House was killed by a bullet that pierced the side of a car driven by a friend.

A house was shot at Tuesday near the freeway, but Martin said investigators have not linked it to the other shootings.

The latest shooting linked to the spree was a Nov. 11 shooting at Hamilton Central Elementary in Obetz, about two miles from the freeway.

The school sits along a rural road lined with pastures, three schools, a church and houses decorated with Christmas lights.

Customers at Hamilton General Store a half-mile down the road already had been sharing alternate driving routes, and Tuesday's news increased their fears, owner Beverly Evans said.

''People are trying to figure out how to stay off 270, but now people aren't sure if that will keep us safe,'' Evans said.

Superintendent Bill Wittman said he believes the shooting at the school was not meant to harm anyone because it happened overnight, but nervous parents expressed concern.

Tiffany Ellis, 32, said her son's second-grade classroom faces the front of the school, where the bullet struck.

''It makes me angry to be honest with you, that I have to drive down the road worrying about getting shot,'' Ellis said Tuesday.

She said she plans to call Wednesday to see what precautions the district is taking, and may avoid her own living room, which also faces the two-lane road.

''That's kind of scary to think someone could shoot through your window like that,'' Ellis said.

Jimmy Eggers said he brought his 8-year-old son to the basketball practice Tuesday night because ''it's hard to stop your daily routine.'' But he added: ''It's definitely scary. You fear for your kid's life.''

At a gas station along the interstate about two miles from the school, emotions ranged from skittish to calm among drivers stopping to fill up.

''The odds are you're not going to get shot,'' said Tom Dixon, 56, of Circleville.

Richard Bailey, 32, disagreed. He uses I-270 each day to get to his job as a shipping manager at Rickenbacker Airport.

''I drive through with my cell phone in my hand every day. It scares me.''

Timeline of 1-270 shootings

Authorities are investigating 12 shootings on or around a southern section of Interstate 270, which circles Columbus. Many of the victims first called law enforcement agencies after hearing of a fatal shooting on Nov. 25:

May 10 - A 37-year-old woman runs out of gas around 4 a.m. in the westbound lanes of I-270 east of I-71. After walking for help, she returns to find the car's windshield shot out and the hood damaged.

Aug. 31 - A 41-year-old woman from Akron finds a bullet hole in the back of her horse trailer hours after driving on eastbound I-270.

Oct. 10 - A woman driving north on U.S. 23 north of I-270 had a flat tire. She didn't know the tire had been shot until she took the flat to be repaired.

Oct. 11 - A 36-year-old man was driving about noon along I-270 when a bullet struck the rear side panel of his Nissan Sentra and exited through the rear window, shattering it.

Oct. 19 - Truck driver William Briggs, 56, of Hilliard, turned north onto westbound I-270 off of U.S. 23 at about 11:30 p.m. and had driven about a mile when the driver's side window exploded.

Nov. 17 - A United Parcel Service truck was eastbound on I-270 around 11 a.m. between Parsons Avenue and U.S. 23 when the driver reported hearing a noise. A bullet hole was found in the door behind the driver's seat.

Nov. 18 - A woman is driving a Ford Explorer around 9:30 p.m. on U.S. 23, north of Rathmell Road when a bullet strikes the driver's side door.

Nov. 21 - Edward Cable, 53, a retired prison guard from Lucasville, reports bullet fired into his minivan about 7:40 p.m. on U.S. 23 south of Rathmell, 1.5 miles from I-270.

Nov. 25 - Gail Knisley, 62, of Washington Court House, is killed about 10 a.m. on I-270 near I-71 when a bullet rips through the driver's door of the Pontiac Grand Am driven by a friend. Four hours later, near the same spot, a GMC Jimmy driven by a 26-year-old man from Orient, just south of Columbus, is struck near the left rear fender.A tractor-trailer driver for Coca-Cola Co. reports finding a hole in the rear door of the trailer after making deliveries along I-270 between 1 p.m. and 3:30 p.m.

Dec. 2 - Authorities confirm a 12th shooting broke a window at a school in Obetz at 1:30 a.m. on Nov. 11. They said four of the shootings were from the same gun and that they believed all the shootings were connected.