Four people were killed and at least nine others were wounded when a shooter opened fire at Apalachee High School in Georgia on Wednesday morning. Two of the victims killed in the shooting were students at the school and the others were teachers, authorities said. They were identified as Mason Schermerhorn, Christian Angulo, Richard Aspinwall and Christina Irimie.

The nine people hospitalized after the shooting had been shot “in some capacity” and all were expected to survive their injuries, Barrow County Sheriff Jud Smith said at a news conference, adding that the group included eight students and one teacher. Barrow County includes Winder, the city about an hour’s drive northeast of Atlanta where Apalachee High School is located.

Authorities have arrested a suspect, 14-year-old Colt Gray, who was a student at the high school. He was taken into custody alive and will be charged with murder and “handled” as an adult, said Georgia Bureau of Investigation Director Chris Hosey.

Here is what we know about the victims so far.

Christina Irimie

Christina Irimie was one of two teachers at Apalachee High School who died in the shooting. She was 53.

She is listed as a mathematics instructor in the staff directory published online by the Barrow County School District.  

Isaac Sanguma, a student at the school who was there when the shooting happened, told “CBS Mornings” that Irimie was his math teacher.

Sanguma recalled speaking to Irimie for the last time on Wednesday morning when, he said, she encouraged him to get to class on time. The high school junior described Irimie as welcoming and said she prioritized instilling a sense of confidence in her students. He also said she was a kind person who told “corny jokes.”

“I didn’t know that was going to be my last time seeing her and talking to her,” Sanguma said. “I just can’t believe my teacher, somebody I see every day … it just don’t feel real.”

Richard Aspinwall

Richard Aspinwall was another math teacher at Apalachee High School who died in the shooting. He was 39.

Aspinwall was an assistant coach for the high school’s football team and a father to two young girls, the Atlanta Journal-Constitution reported. The head football coach, Mike Hancock, told the outlet that Aspinwall would hug his wife, Shayna, and their children in the end zone after every game.

He formerly served as the secondary football coach at Mountain View High School in Lawrenceville, Georgia, according to that school’s football team. 

“With deepest sympathy we share that former MV secondary coach Ricky Aspinwall was tragically lost during the senseless act at a nearby high school today,” reads a message posted on social media by the Mountain View Bears. “Coach A was a beloved member of MVHS football and the school’s math department. We pray for Shayna and his girls.”

Christian Angulo

Angulo was one of two students killed in the shooting at Apalachee High School. He was 14.

A GoFundMe campaign created by Lisette Angulo, who identified herself as Angulo’s oldest sister, describes him as “a very good kid” who was “very sweet and so caring.”

“He was so loved by many,” it reads. “His loss was so sudden and unexpected.. We are truly heartbroken.. He really didn’t deserve this.”

Angulo’s family has asked for donations to help support their funeral expenses. As of Thursday afternoon, the campaign had already raised more than $40,000, far exceeding its original goal.

Mason Schermerhorn

Mason Schermerhorn was the other student killed in Wednesday’s school shooting. Like Angulo, Schermerhorn was also 14.

Friends of Schermerhorn’s family told the New York Times that he was a family-oriented teenager who “really enjoyed life.” One of them, identified by the newspaper as 40-year-old Doug Kilburn, said Schermerhorn “always had an upbeat attitude about everything.” Louis Briscoe, a coworker and friend of Schermerhorn’s mother, said the teenager and his family were looking forward to their upcoming vacation at Disney World, the New York Times reported.