A 14-year-old Georgia high school student has been charged as an adult with using an assault-style rifle to kill two students and two teachers in the hallway outside his algebra classroom, according to authorities.

The shooting at Apalachee High School in Winder, about an hour's drive from Atlanta, was the latest among dozens of school shootings across the U.S. in recent years, including especially deadly ones in Newtown, Connecticut; Parkland, Florida; and Uvalde, Texas.

Here's what's known about the victims of Wednesday's shooting:

Christian Angulo, 14

Angulo's older sister, Lisette, wrote in a GoFundMe fundraiser seeking donations to help with funeral costs that they were heartbroken by the loss of her "baby brother."

"He was a very good kid and very sweet and so caring. He was so loved by many. His loss was so sudden and unexpected," she wrote. "He really didn't deserve this."

Mason Schermerhorn, 14

Louis Briscoe told The New York Times that when he learned of the shooting, he called Schermerhorn's mother, a friend and co-worker. She told him "Mason's gone," and his heart dropped.

"Nobody should have to go through this type of pain," Briscoe said.

Family friends said Schermerhorn recently started at the high school and liked telling jokes, reading, video games and Walt Disney World.

"He really enjoyed life," said Doug Kilburn, a friend of Schermerhorn's mother. "He always had an upbeat attitude about everything."

Christina Irimie, 53

Silvia Pasch told The Atlanta Journal-Constitution she got to know Irimie, a math teacher, when they volunteered at Saints Constantine and Helen Church in Lilburn, which holds festivals to celebrate Romanian culture. She said Irimie's practice with the children's dance group this spring included a lesson for a student struggling with an algebra concept. Pasch said she listened in as she chopped vegetables in the kitchen "because I thought I might learn something." Without Irimie, the next festival will be hard, Pasch said.

"I bet when we are cutting potatoes and vegetables we will talk about her," she said.

Nicolae Clempus told the newspaper Irimie made him feel welcome when he moved to the United States in 2001. She was active in the expat community after immigrating from Romania a few years earlier. The priest at Saint Mary Romanian Orthodox Church in Dacula described Irimie as someone "you know you can count on" and who always volunteered at events by cooking or dancing.

Irimie, who was part of a traditional Romanian dance group from the Transylvania region when she was younger, later became an instructor and had a gift for working with young people, Clempus said.

Richard Aspinwall, 39

Apalachee High School football coach Mike Hancock told the Athens Banner-Herald the team's defensive coordinator, who was also a math teacher, was a great man and father who loved his daughters and wife, loved football and was well-respected.

"He worked his tail off," Hancock said. "He coached old-school ways, but he loved those kids."

Junior and former football player Jay Garcia, attended a prayer vigil at a downtown Winder park Wednesday to remember the coach and teacher who helped him a lot, both in learning football and in life.

"You can't bring back the dead," Garcia said. "I understand some people won't be here tomorrow and just never forget who they are and what they meant to you."