Area hospitals reported Friday that they had treated 14 people for injuries related to the shooting.
A hospital treating three of the 13 wounded said one patient, a minor, was in good condition and the other two were critical.
"My heart is so heavy for the students of Santa Fe High School".
A student, Daymon Rabon, said he was in class when he heard a loud bang next door.
Students at a Texas high school where a gunman killed 10 people are being allowed inside the building to get auto keys and other belongings they left behind. He said about 50 students had been admitted as of Saturday afternoon and that others would be allowed in for about three more hours. Braun and other officials declined to answer questions about the investigation.
A 16-year-old boy who says he considers Pagourtzis a friend says he is interested in guns and war simulation video games, but that he has never about talked about killing people.
The safety chief for the county's schools, Thomas Trawick, says the shots were fired in a Mount Zion High School parking lot after an argument between people who had attended a ceremony for graduates of the Perry Learning Center, which prepares students for careers as an alternative to traditional high schools. Braun says the officer remains in critical condition.
A Texas official says explosive devices found with the suspected gunman at a high school near Houston weren't capable of detonating.
The assailant's homemade explosives included pipe bombs, at least one Molotov cocktail and pressure-cooker bombs similar to those used in the Boston Marathon attack, authorities said.
Pagourtzis plays on the Santa Fe High School junior varsity football team, and is a member of a dance squad with a local Greek Orthodox church.
Pagourtzis is being held in the Galveston County Jail without bond on a capital murder charge.
Realizing it was the school where his 18-year-old daughter, Sabika, was an exchange student, he flipped through channels trying to learn more and left her messages, but she didn't reply.
He called his daughter's friends, but they weren't responding either.
It was a sunny Friday morning at Santa Fe High School and the students and teachers were excited about the weekend with the end of the school year just two weeks away. She was coming back soon. He says he thought she would be safe in the U.S.
Tristen Patterson, a junior at Sante Fe high School, says Pagourtzis didn't show signs of being bullied, but that he rarely talked about himself.
Mr Poehl, the suspect's lawyer, said he expected a second hearing soon and would likely have more information about that on Monday.
He says authorities recovered a couple of explosive devices at the school and "several" in Pagourtzis' vehicle and home, and that they've been sent for testing to the Federal Bureau of Investigation laboratory in Quantico, Virginia.
"While we remain mostly in the dark about the specifics of (Friday's) tragedy, what we have learned from media reports seems incompatible with the boy we love", the family said. Santa Fe is roughly 36 miles outside of Houston. It was also the 10th since the February massacre at Marjory Stoneman Douglas High School in Parkland, Florida, which left 17 dead and sparked a nationwide conversation about gun violence in America.
Classmate David Hogg, who helped start the #NeverAgain movement with Corin, predicted that politicians would descend on the Texas campus acting like they care to boost their approval ratings. Those screenings can lead to psychiatric appointments and sometimes immediate hospitalizations and arrests for planning violent incidents like shootings, according to an April 30 brief that Tech's Health Sciences Center published about the program.