A Plano elementary school was locked down Friday afternoon after gunshots struck a nearby fire station.
Firefighters said at least 10 rounds struck Fire Station No. 11.
"I heard what sounded like a lightbulb dropping and breaking," said firefighter Mark Nugent, who was on duty when the gunfire started. "And the van out back, the glass shattered on it, and I turned around and told the guys, 'I think we're being shot at. You all might want to get down.' Of course, being at a fire station, they all thought I was kidding."
Then another round shattered a glass window on the garage door.
"And they knew I wasn't kidding," Nugent said. "Everyone just sort of ran for cover. I ran inside and got on the PA and told everyone to hunker down, we're being shot at."
Police evacuated the firefighters in an armored vehicle.
"It was a little spooky, but it wasn't too bad," Nugent said.
McCall Elementary School, which is approximately a half-mile away, was locked down as a precaution while law enforcement investigated.
Plano police were joined by a helicopter from the Texas Department of Public Safety in canvassing the Los Rios area, but they did not locate the gunman and did not hear any gunfire.
Police found evidence of "extensive shooting of .22-caliber weapons" in a creekbed near the fire station, including targets and empty boxes of .22 ammo.
"It's our opinion based on the evidence we found that somebody was in that creek target shooting," Officer David Tilley said. "Apparently they're a really bad shot."
The fire station window and vehicle window were down range from and in-line with the creek, police said.
Tilley said investigators do not think the shooting was intentional.
"We don't believe there was any malice or intent to shoot at the fire station," he said.
Workers in the area told police they heard gunfire in the creek a couple of days earlier.
Nugent said he has some advice for the shooter: "Practice your rifle safety and make sure you got a clear backstop is the first thing I'd like to say."
He has been a Plano firefighter for 29 years.
"After this many years, I've always considered myself lucky that I haven't been hurt or anything," he said. "I'm thinking about retirement pretty serious. And I thought, you know, I may have to rethink this. It may come quicker."
Early in the search, officers suspected the gunfire may have come from a hunter because it is dove season.
The Los Rios area of Plano is near the Oak Point Park and Nature Preserve and not as suburban as the rest of Plano. It is fairly common for people to hunt dove on several acres of open land, even it's illegal to shoot a gun within the city limits.
Police continue to investigate the incident.
McCall Elementary typically dismisses school at 2:45 p.m. Most of the students were held after, but later sent home. The children were released in a staggered rotation -- first were those whose parents picked them up, followed by bused students and finally those who walk to and from school.
NBC 5's Susy Solis contributed to this report.