Colt Gray, 14, surrendered when “engaged by school resource officers inside the school”, Barrow County police said.
He is accused of committing the fatal shootings with an assault-style rifle outside his algebra classroom.
One of his classmates, Lyela Sayarath, said she heard 10 to 15 gunshots.
Kassidy Reed, 17, joined classmates seeking counselling on Thursday and said she had struggled to sleep.
After the shooting, she said she saw blood in the hallway and what looked like a disassembled firearm lying next to a body.
“The first thing you wake up and think about is like, somebody lost the coach, somebody lost their dad, somebody lost their best friend,” she said.
Image: Students and staff gather next to a football field at the school. Pic: Reuters
Nine people – one teacher and eight students – were wounded in the shooting. They remained in hospital on Thursday, NBC News, Sky News’s partner network, reported.
All are expected to survive, Barrow County Sheriff Jud Smith said.
Neither body camera videos nor audio will be released to “protect the integrity of the investigation”, the sheriff’s office said.
Following a tip off from the FBI, Gray and his father were interviewed last year in connection with online threats about a school shooting made on the gaming platform Discord.
They denied making the comments, investigators said.
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School shooting suspect previously investigated by FBI
The case was closed after neither Gray could be connected to the Discord account, while no grounds were found to confiscate the family’s guns, according to police reports released by the sheriff’s office.
Information on the Discord account – which had profile information in Russian and a digital evidence trail indicating it had been accessed in different Georgia cities and Buffalo, New York – was “inconsistent”, an investigator said.
“This case was worked, and at the time the boy was 13, and it wasn’t enough to substantiate,” Jackson County Sheriff Janis Mangum said.
“We did not drop the ball at all on this. We did all we could do with what we had at the time.”
Gray’s father told officials he had hunting guns locked in a safe in the house and his son did not have access to them.
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Gray has been charged as an adult over the deaths of students Mason Schermerhorn and Christian Angulo, both 14, and teachers Richard Aspinwall, 39, and Christina Irimie, 53, according to Chris Hosey, director of the Georgia Bureau of Investigation.
He is due to make his first court appearance on Friday.
Classes at the school were cancelled on Thursday, though some people arrived with flowers.
Israel has shown little respect for international borders since becoming the unrivalled military hegemon of the Middle East. Today that meant an Israeli airstrike on a government building in Damascus.
Israel has moved into parts of the south of the country, built military bases and declared a line of control.
Image: Smoke rises from an Israeli airstrike that hit the Syrian Defence Ministry in Damascus. Pic: AP
On Monday, Syrian tanks heading south to try and restore order following an outbreak of factional fighting were attacked by Israeli warplanes.
“The presence of such vehicles in southern Syria could pose a threat to Israel,” stated the Israel Defence Forces.
In reality, Syria’s ageing tanks pose minimal threat to Israel’s state-of-the art military.
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Syrian presenter interrupted by Israeli airstrike
The Syrian armour was attacked as it entered the area around Sweida in the Druze heartland of southern Syria following factional fighting there.
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The flare-up reportedly began with clashes between Bedouin and Druze groups that ended in scores killed.
The background to the escalation is complicated.
At least three Druze militia groups are divided in their loyalties to different religious leaders and differ over how they should respond to calls to assimilate into the new post-revolutionary Syria.
Image: Druze from Syria and Israel protest on the Israeli-Syrian border.
Pic: AP
Israel is becoming more and more involved in Syria’s internecine war and says it will remain there indefinitely “to protect our communities and thwart any threat”.
Its critics say Israel is operating a policy of divide and rule in Syria, weakening the fledgling government and creating a buffer zone to protect the border with the Golan Heights – originally Syrian territory that it has occupied and annexed for almost half a century.
Since the fall of the Assad regime, Israel has used airstrikes to destroy of much of Syria’s military capability weakening its ability to impose control on outlying regions. This makes it more not less likely Israel will have a volatile unstable state on its northern border.
Image: Syrian security forces walk along a street in the southern Druze city of Sweida. Pic: Reuters
America and European powers have chosen to normalise relations with the new government in Damascus and lift sanctions.
In contrast Israel has occupied its territory, bombed its military and today hit one of its government buildings in the capital with an airstrike.
Since its crushing military campaigns against Hamas, Hezbollah and Iran, Israel has emerged as the unchallenged military power of the region.
There is however a limit to what blunt force can achieve alone. It requires diplomacy to achieve lasting gains and Israel’s repeated assaults on multiple neighbours combined with its relentless campaign in Gaza are winning it few friends in the region.
Israeli airstrikes have targeted the Syrian military headquarters in Damascus amid renewed clashes in the country.
The gate of the Ministry of Defence in the Syrian capital was targeted by two warning missiles from an Israeli reconnaissance aircraft.
State-owned Elekhbariya TV said the Israeli strike had wounded two civilians, the Reuters news agency reported.
Image: Smoke rises from Syria’s defence ministry building in Damascus. Pic: Reuters
It came as Israeli airstrikes targeted security and army vehicles in the southern city of Sweida, where the Druze faith is one of the major religious groups – marking the third consecutive day Israel has struck Syrian forces.
The Israeli military confirmed it had “struck the entrance gate” in Damascus – and that it would be monitoring “actions being taken against Druze civilians in southern Syria”.
Image: The Israeli airstrike targeted Syria’s military headquarters. Pic: AP
Why Israel is getting involved in Syria’s internal fighting
Israel has shown little respect for international borders since becoming the unrivalled military hegemon of the Middle East. Today that meant an Israeli airstrike on a government building in Damascus.
Israel says its attack on a Syrian defence ministry facility was intended as a warning to the new government: stay out of the part of southern Syria we have occupied or else.
Israel has moved into parts of the south of the country, built military bases and declared a line of control.
On Monday, Syrian tanks heading south to try and restore order following an outbreak of factional fighting were attacked by Israeli warplanes.
“The presence of such vehicles in southern Syria could pose a threat to Israel,” stated the Israel Defence Forces.
In reality, Syria’s ageing tanks pose minimal threat to Israel’s state-of-the art military.
Local media said Sweida and nearby villages were coming under heavy artillery and mortar fire on Wednesday, according to Reuters.
The clashes marked the collapse of a ceasefire between Syrian government forces and Druze armed groups, with Israel also warning it would increase its involvement.
Image: Syria said its forces had responded to being fired upon. Pic: Reuters
Israel said it was acting to protect the Druze groups through its attacks on convoys of Syrian forces.
Syria blamed militias in Sweida for violating a ceasefire agreement which had only been reached on Tuesday.
A statement from its defence ministry said: “Military forces continue to respond to the source of fire inside the city of Sweida, while adhering to rules of engagement to protect residents, prevent harm, and ensure the safe return of those who left the city back to their homes.”
Israel’s defence minister Israel Katz said the military will continue to strike Syrian forces until they withdraw and should “leave Druze alone”, according to local reports.
At least 20 people have been killed in an incident in Khan Younis, according to the Gaza Humanitarian Foundation (GHF), an Israel and US-backed organisation.
In a statement, it said 19 people were trampled and one was stabbed in a surge “driven by agitators in the crowd”.
“We have credible reason to believe that elements within the crowd – armed and affiliated with Hamas – deliberately fomented the unrest,” it said.
“For the first time since operations began, GHF personnel identified multiple firearms in the crowd, one of which was confiscated. An American worker was also threatened with a firearm by a member of the crowd during the incident.”
It provided no evidence to support the claim.
The Hamas-run Gaza health ministry claimed 21 Palestinians were killed, “including 15 who died of suffocation as a result of tear gas fired at the starving people and the subsequent stampede” at the GHF site.
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Gaza deaths increase when aid sites open
The statement is unusual for the GHF, as the controversial group, which has been rejected by the United Nations and other aid groups, rarely acknowledges trouble at its distribution sites.
The GHF began distributing food packages in Gaza at the end of May, after Israel eased its 11-week blockade of aid into the territory.
It has four distribution centres, three of which are in the southern Gaza Strip. The sites, kept off-limits to independent media, are guarded by private security contractors and located in zones where the Israeli military operates.
Analysis: Gazans face unbearable choice of risking their lives for supplies or going hungry
by Lisa Holland, Sky News correspondent in Jerusalem
The United Nations has already condemned the aid centres run by the Gaza Humanitarian Foundation as “death traps” – and that was before the latest loss of life, seemingly mostly from suffocation.
It’s the first and only time we know of people dying in this way, waiting to get food. Although the Gaza health ministry and the GHF dispute exactly what happened.
But how much longer can this Israeli and American-backed way to supply aid continue when people are dying on a near-daily basis?
However it happened, Gaza’s overcrowded hospitals are once again overwhelmed.
And there are serious questions to answer about the organisation of a system which is supposed to be providing humanitarian aid to desperately hungry people, but instead is a place where there is so much loss of life.
It leaves people with an unbearable choice between risking their lives to get supplies or going hungry.
Palestinian witnesses say Israeli forces have repeatedly opened fire towards crowds of people going to receive aid.
The Israeli military says it has fired warning shots at people who have behaved in what it says is a suspicious manner. It says its forces operate near the aid sites to stop supplies from falling into the hands of militants.
After the deaths of hundreds of Palestinians trying to reach the aid hubs, the UN has called the GHF’s aid model “inherently unsafe” and a violation of humanitarian impartiality standards.
In response, a GHF spokesperson said: “The fact is the most deadly attacks on aid sites have been linked to UN convoys.”
Image: People carry distributed aid supplies in Khan Yunis, southern Gaza. File pic: AP
The GHF says it has delivered more than 70 million meals to Gazans in five weeks and claims other humanitarian groups – which refuse to work with the GHF – had “nearly all of their aid looted” by Hamas or criminal gangs.
Since the GHF sites began operating, more than 875 people have been killed while receiving aid, both at GHF distribution points or elsewhere, according to the UN human rights office and the Hamas-run Gaza health ministry.
At least 674 of those have been killed in the vicinity of aid distribution sites run by the GHF.