Governor Greg Abbott confirms 10 deaths and 10 others wounded.
Officials have identified Dimitrios Pagourtzis as the shooter in custody. Officials also said the gunman was injured.
A law official has reported that 10 people are dead, nine students and one teacher. Two law enforcement officials are among those injured.
Pipe bombs and pressure cookers were also found at the school.
Santa Fe Police have confirmed that explosives have been found inside Santa Fe High School and in the surrounding area.
Doctors at a local hospital say they're treating one student with a gunshot wound along with one middle-aged woman and one middle-aged man. One patient is in critical condition.
Police believe the person detained is also a student along with the suspected student gunman. Police are searching Santa Fe High School for any explosive devices.
Eight people have been confirmed dead. Two adults and one person under the age of 18 are being treated at a local hospital for gunshot wounds.
The sheriff said one person is in custody and one person is detained. A police officer has also been injured.
The assistant principal of Santa Fe High School said the active shooter has been taken down and arrested.