An emergency vehicle and police near the scene of the Santa Fe High School after police found explosives at the school where a shooting left several people dead in Santa Fe, Texas, U.S., May 18, 2018.

People console each other during a vigil held after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

A note is left behind by an attendee on the vigil table during a vigil for the victims of a shooting at Santa Fe High School that left several dead and injured in Santa Fe, Texas, U.S., May 18, 2018.

Daniel Hernandez, a local imam, prays with his two sons near the site of the shooting at the Santa Fe High School, in Santa Fe, Texas, U.S., May 19, 2018.

Police vehicles line the blocked-off street where the home of Dimitrios Pagourtzis, the suspect in the Santa Fe High School shooting, is located in Alvin, Texas, May 18, 2018.

Students embrace during a vigil held at the Texas First Bank after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

Aziz Shaikh (L), father of Sabika Aziz Sheikh, a Pakistani exchange student, who was killed with others when a gunman attacked Santa Fe High School in Santa Fe, Texas, U.S., comforts a relative in Karachi, Pakistan May 19, 2018.

Daniel Hernandez, a local imam, comforts Dih-Anaa Forero of Missouri City, near the site of the shooting at the Santa Fe High School, in Santa Fe, Texas, U.S., May 19, 2018.

Mourners bow their heads in prayer during a vigil held after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018. Reuters/Trish Badger

Attendees light candles to pay their respects to the victims of a shooting at Santa Fe High School that left several dead and injured in Santa Fe, Texas, U.S., May 18, 2018.

Students from Texas City pray outside of the Santa Fe High School in Santa Fe, Texas, U.S., May 19, 2018.

Police keep a roadblock in front of the Santa Fe High School after police found explosives at the school where shooting left several people dead

People gather in prayer during a vigil held at the Texas First Bank after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

Ali Aziz Shaikh 12, brother of Sabika Aziz Sheikh, a Pakistani exchange student, who was killed with others when a gunman attacked Santa Fe High School in Santa Fe, Texas, U.S., poses for a photo with her shield prize at their residence in Karachi, Pakistan May 19, 2018.

Law enforcement officers are responding to Santa Fe High School following a shooting incident in this Harris County Sheriff office, Santa Fe, Texas, U.S., photo released on May 18, 2018.

Candles line a table during a vigil held at the Texas First Bank after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

Soha Aziz Shaikh 10, sister of Sabika Aziz Sheikh, a Pakistani exchange student, who was killed with others when a gunman attacked Santa Fe High School in Santa Fe, Texas, U.S., sits in a room with relatives, at her residence in Karachi, Pakistan May 19, 2018.

Aziz Shaikh (L), father of Sabika Aziz Sheikh, a Pakistani exchange student, who was killed with others when a gunman attacked Santa Fe High School in Santa Fe, Texas, U.S., is comforted by a relative at his residence in Karachi, Pakistan May 19, 2018.

Flags fly at half mast outside the Galveston County Jail in Galveston, Texas, U.S., where suspect Dimitrios Pagourtzis was charged in connection with a shooting that left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

Police keep a roadblock on a main road to Santa Fe High School where police found explosives after an early morning shool shooting that left several people dead in Santa Fe, Texas, U.S., May 18, 2018.

Students light candles during a vigil held after a shooting left several people dead at Santa Fe High School in Santa Fe, Texas, U.S., May 18, 2018.

Christian Cardenas 10, helps Jaydon Johnson 8, light a candle during a vigil for the victims of a shooting at Santa Fe High School that left several dead and injured in Santa Fe, Texas, U.S., May 18, 2018.

Police tape is seen near the site of the shooting at the Santa Fe High School, in Santa Fe, Texas, U.S., May 19, 2018.