EDINBURG, Texas -- Three deer hunters suspected of possibly firing the shots that wounded two South Texas middle school students were taken in for questioning, but investigators hadn't determined early Tuesday whether the shootings were accidental, reckless or intentional, a sheriff said.
Hidalgo County Sheriff Lupe Trevino told The Associated Press that authorities have theorized that the students were hit by "errant or stray bullets" fired from hunting pastures near the middle school, which was hosting outdoor tryouts for the basketball team.
Three hunters were taken in for questioning Monday night but were not immediately arrested, he said. Authorities planned to search Tuesday morning for rifle casings to see if they match the barrel markings on the guns the hunters questioned had in their possession, he said.
"It's undetermined if it was intentional, someone was reckless, or a plain old accident," Trevino said. "We just don't know yet. We're going to continue to see what the three people have got to say for themselves, see if we can piece that together."
Two students, ages 13 and 14, were wounded in the Monday afternoon shootings outside Harwell Middle School near Edinburg.
One was in critical condition Monday night with a gunshot wound in in the back and a bullet embedded in an organ, while the other was in stable condition with a gunshot wound to the armpit, Trevino said.
Even if accidental, investigators will want to know how close the shooters were to the school when they opened fire. Trevino said two hunting pastures are within 600 yards of the school.
Classes were to go on as scheduled Tuesday, but with increased security and counselors available to speak with students, said Edinburg school district spokesman Gilbert Tagle.
At the time of the shooting, one of the boys was going for a layup. The other was waiting his turn to try out, Trevino said.
A number of after-school activities besides the basketball tryouts were going on at the school, including a concert and a faculty meeting, Tagle said. He estimated as many as 200 children could have been on campus.
Classes were not in session when the shooting happened, but the school complex was immediately placed on lockdown.
Harwell Middle School opened just this year on the rural property northeast of Edinburg, which is about 50 miles northwest of Brownsville. Homes line the road approaching the school, but open fields stretch out behind it and to the north.
Gangs have been a problem at the school, said Harrell eighth-grader Samuel Cepeda, 15, and he has worried about security. However, Trevino said investigators do not believe the shooting was gang-related.
The outdoor court where the shooting took place was north of the school complex at an athletic facility that includes a football field, track and tennis courts, said fellow eighth-grader Oziel Garcia, 14.
Eighth-grader Annette Vargas Ugalde, 15, said she was about to board her bus near the gym after school when school officials started rushing students indoors.
"They told us to, 'Get inside, get inside,'" she said.
She said she heard no shots but saw a group of people on the outdoor court standing near one boy on the ground. A school nurse tended to him while another boy was sitting up.
Annett said she boarded her bus, and it left.
More content from msnbc.com and NBC News:
- First Read: Why Romney still has a fighting chance
- Bill would permit robo-calls to your cell phone
- What does it take to be rich? About $150K, apparently
- Long-sought 'God particle' cornered, scientists say