A 14-year-old boy has been arrested on suspicion of murder after two students and two teachers were shot dead at a US high school.
Nine others were injured in the incident which happened in Winder near Atlanta, Georgia on Wednesday.
The suspect, named by police Colt Gray, had been previously investigated by police over threats to carry out a similar attack last year.
He was a student at Apalachee High School in Barrow County where the attack took place, leading to the school being placed on lockdown and officers swarming the location before he gave himself up.
The four victims who died have been named as students Mason Schermerhorn and Christian Angulo, both 14, and teachers Richard Aspenwall (39) and Christina Irimie (53).
Christian was described as "a very good kid and very sweet and so caring" by his older sister Lisette Angulo.
"He was so loved by many. His loss was so sudden and unexpected.. We are truly heartbroken.. He really didn't deserve this," she added.
Law enforcement arrive as students are evacuated to the football stadium after Apalachee High School was placed on lockdown during a school shooting, 4-9-24. Image: Associated Press / AlamyIn May last year, the FBI received several anonymous tips about online threats to commit a school shooting, Chris Hosey, director at the Georgia Bureau of Investigation said.
The Jackson County Sheriff's Office located a possible suspect, he said - the then 13-year-old Gray.
They interviewed Gray and his father, who stated he had hunting guns but that his son didn't have unsupervised access to them.
Gray himself denied making the threats online and at the time there was no probable cause for arrest and no further action was taken, Mr Hosey said.
Authorities are now re-investigating the incident and any possible connection it may have to the most recent shooting.
"We are also aware of some previous contacts that the Department of Family and Children Services had had with the suspect and his family, and we are pursuing that avenue as well," Mr Hosey added.
The eight students and one teacher were taken to hospital with injuries from the attack but they are all expected to make a recovery.
Gray is being charged as an adult and the attack was carried out using an AR-style weapon - a gun often associated with school shootings.
While police are still chasing down a number of leads and carrying out investigations, they said that the actions of teachers saved a number of lives.
Authorities were alerted to the attack due to a new alarm system that had only been implemented a week earlier.
Sheriff Jud Smith said: "All of our teachers are armed with a form of ID, this alarms us and alerts law enforcement officers after buttons are pressed on the ID.
"It alerts us there is an active situation at the school. We've had that about a week now."
Brandy Rickaba and her daughter Emilie pray during a candlelight vigil for students and teachers at Apalachee High School following a school shooting, 4-9-24. Image: Associated Press / AlamyThe words "hard lockdown" appeared on a screen in Layla Ferrell's health class as lights began flashing.
She and her terrified classmates piled desks and chairs in front of the door to create a barrier, she said.
Kaylee Abner, meanwhile, was in her geometry class when she heard gunshots.
Along with her classmates she hid behind their teacher's desk, before they began flipping the desk to try and barricade the classroom door, she said.
Ashley Enoh was at home on Wednesday morning when she got a text from her brother, who is a senior at the school.
The message said: "Just so you know, I love you."
When she asked in the family group chat what was going on, he said there was a gunman at the school.
Reporting by: IRN
