A 15-year-old student shot a teacher at a Texas high school and then fatally shot himself Monday, according to authorities, who were still investigating what led to the early morning attack.

No other injuries were reported at Hill Country College Preparatory High School in Bulverde, a small but growing city near San Antonio.

The teacher was taken to a nearby hospital. Comal County Sheriff Mark Reynolds said hours after the shooting that he did not know her condition.

“What happened today is something no community ever wants to face, but we prepare for something that we hope never occurs,” Reynolds said.

He said the student shot the teacher before turning the gun on himself. Reynolds said investigators were working to understand the relationship between the student and the teacher and looking into how the firearm was obtained.

The small campus of roughly 250 students was placed on lockdown shortly after 8:30 a.m., according to the school. One student told San Antonio television station KSAT that they heard loud bangs coming from a room on the second floor and then heard screaming.

Another student told the TV station that she heard five shots and yelling before her debate teacher told students to get inside a classroom.

Students were bused to a nearby middle school, where parents stood in long lines, some praying, as they waited to be reunited. Reynolds said the family members of the shooter had also gone into reunification line.

“We’re trying to collect as much information as we can from witnesses,” Reynolds said.