The New York Times reports that a teenage boy has been arrested as a suspect in a school shooting that killed 10 people and injured 10 others today in Santa Fe, Texas. The young man was carrying a sawed-off shotgun and .38 revolver that were smuggled into the school under his coat.

The suspect is an introvert but gave few signs he may be prone to carrying out such a crime. He surrendered to police and was taken into custody. Two explosive devices were also found at the school. This marks the worst school shooting since the one in Parkland, Florida in February.

Early Friday morning, around 7:30 a.m., the first shots rang out in the halls of Santa Fe High School, located just 35 miles outside of Houston. The suspect reportedly entered an art classroom, yelled “Surprise!” and opened fire, and students began to run. The shooter was wearing a trench coat and combat boots. His ex-girlfriend was one of the victims shot in that room.

A student witness tells the media that he was outside of his history class when the fire alarm went off and he ran outside through a side door. He heard rapid gunfire on his way out.

Billie Scheumack, 68, is a nearby resident who saw students running down her street just a block from the school, clutching their cell phones. Her neighbor told her some students had been shot.

At a press conference Friday, police stated that two officers were on campus when the shooting broke out and were able to stop it before more damage could be done. It was also stated that though there were not any warning signs about the victim’s plans, there were plans about the attack found on his phone and computer. These included the fact that he wanted to carry out the shooting, then commit suicide.

The weapons used in the attack were obtained legally by the suspect’s father.

*Photo credit Jennifer Reynolds/The Galveston County Daily News, via Associated Press