A law enforcement official says 10 people are dead in the Texas high school shooting; nine of those killed are students and one a teacher.

Two law enforcement officers are among those injured at Santa Fe High School, the official says.

As to the explosive devices at the school, the official says pipe bombs and pressure cookers were found at the scene.

This is the third school shooting in eight days, and the 22nd since the beginning of the year in the United States.

A 17-year-old male student suspected in the shooting is in custody.

A second person — also believed to be a student — has been detained as well, Gonzalez said.

Most of the dead are students, the sheriff said.

Witnesses described students running from the school as they heard gunshots; they also described hearing an alarm at the school, though the sequence of events wasn’t immediately clear.

An armed person walked into an art class at the school and began firing what looked like a shotgun, a witness told CNN affiliate KTRK.

The witness told KTRK she saw a girl shot in the leg.

Patients from the school are being taken to a hospital in Galveston, hospital spokesman Raul Reyes said. He did not say how many or give details about the injuries. At least one police officer was injured, Sheriff Gonzalez said.

Witnesses describe hearing an alarm and gunfire

Angelica Martinez, a 14-year-old student, told CNN she and her schoolmates were being evacuated at one point “like it’s a fire drill.”

“We were all standing (outside), but not even five minutes later, we started hearing gunshots,” she said. “And then everybody starts running, but like the teachers are telling us to stay put, but we’re all just running away.”

“I didn’t see anybody shooting, but like (the gunshots) were kind of spaced,” Angelica said, adding she heard about four shots.

The witness who spoke to KTRK also said she heard an alarm. She didn’t specify if that was before or after the gunfire she described in the art class.

She said she couldn’t describe the shooter.

“I didn’t look. I just ran,” she said.

Another student, Dakota Shrader, told CNN affiliate KPRC that she heard gunshots only after hearing an alarm in the school.

“I was in the history hallway, and as soon as we heard the alarms, everybody just started leaving following the same procedure as … (a) practice fire drill,” Shrader said, breaking into tears. “And next thing you know, we just hear … three gunshots, loud explosions, and all the teachers are telling us to run.”

The entire school district is on lockdown, district officials said.

The high school has about 1,400 students, according to GreatSchools.org.

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