(CNN) -- Steve Maida was leaving the cafe on his college campus Tuesday when he saw people running. Then, he heard a girl scream: "My friend's been stabbed."
Maida said he saw blood on a stairway and several injured victims at the Lone Star College's CyFair campus northwest of Houston, Texas. One wounded woman had a hole her throat, one had a hole in her cheek and another victim had a stab wound in the back of his head, Maida said.
"I just took off downstairs running" and searching for the attacker, he said.
Maida told CNN he was among a group of students that chased the suspect, tackled him and pinned him down until authorities arrived. Investigators could not be immediately reached to confirm his account.
"I couldn't run the other way like everyone else was," he said.
Harris County Sheriff Adrian Garcia told reporters that 14 people were injured in the attack and two of them were in critical condition.
The suspect, an approximately 21-year-old male enrolled at the school, is in custody while authorities continue their investigation, Garcia said.
It was unclear what his motive was, or what weapon he used, Garcia said.
"We do not know exactly what type of weapon was used other than to say that it is at this point an unknown instrument," he said. "We don't know whether a knife or some other type of instrument."
Another student, Maya Khalil, was shocked when she saw victims bleeding on the ground.
Moments before, the 19-year-old had been in class in the health sciences building.
"It was really scary," she told CNN.
Khalil snapped photos of the chaos as it unfolded, posting pictures on Twitter that showed a bandaged student on a stretcher and police and paramedics swarming the scene.
Garcia said a call came in to 911 Tuesday morning describing a "male on the loose stabbing people" at the Lone Star College's CyFair campus.
Most of the victims had lacerations in their head and neck areas, said Robert Rasa, a spokesman for the CyFair Volunteer Fire Department.
"We were literally going from building to building, room to room, looking for patients, setting up triage," he said.
The school was on lockdown Tuesday afternoon while authorities combed the campus to ensure no other injured people or attackers were there, Harris County sheriff's spokesman Alan Bernstein said.
While authorities investigated, teachers and students huddled together in locked rooms, said Marianna Sviland, a teacher at the college who was in a faculty workroom at the time of the stabbing.
"Outside the window, I saw cops running around, I saw students running and I realized something was going on," she said. "It was scary."
By 2 p.m. (3 p.m. ET), students and staff were allowed to leave campus, Sviland said.
Details about the victim's injuries were unclear Tuesday afternoon.
Bernstein said it wasn't clear whether all of the injured people were stabbed.
"It's possible other people were running away" and became injured that way, he said.
Four injured victims "were in a dire enough situation that they were taken out on helicopters," Bernstein said.
"I do believe the confrontation was limited to a few (classrooms) or just one classroom -- not anybody roaming around and getting into a large number of areas," Bernstein said.
The school posted a warning on its website: "Stay away from the area. Seek shelter in a secure location until the incident is resolved."
Tuesday's incident comes more than two months after three people were wounded in a shooting at a different Lone Star College campus -- the North Harris campus in Houston.