The 16-year-old defendant, who cannot be named, is accused of killing Aria Thorpe at her home in Weston-super-Mare, Somerset, on 15 December 2025.
She died from a single stab wound to her heart and lung.
The jury at Bristol Crown Court heard the defendant, who was 15 at the time, had been seen on CCTV at Worle train station just minutes after the attack.
Footage from the train station played in court appears to show the defendant talking to a group of young people on the platform who he knew from school.
In a police interview, one girl from the group, who was aged 12 at the time, described how the defendant was "trying to get away as quick as he could".
She said: "He was shaking a lot. He just kept saying, 'I need to get away'."
When asked what he needed to get away from, the court was told he replied: "Everything. The police... everything."
The girl said that one member of the group asked whether he had killed someone, as a joke.
She described how the teenager did not respond, but just smiled.
The defendant is seen in footage running to a train on the opposite platform.
Minutes later, police boarded and led him away.
The court also heard from a man who performed CPR on Aria after finding her lying "face down" with her school top "covered in blood."
Ollie Sheppard, a family friend who had been staying at the home, was asked about the moment he returned to the property from work nearby.
"I thought nobody was home, it was quiet," he said.
He added the house was "very eerie", saying: "It felt cold and weird. Everything was silent. I shouted out 'hello, is anyone home?'. I turned around, I see Aria on the floor."
He told the jury he thought Aria was "messing around".
"I could see there was blood on her arm, and her school top was covered in blood," he said.
Mr Sheppard described how his first instinct was to call Aria's mother - but there was no answer.
He then called 999, and was instructed to begin CPR.
"Obviously, when I first rolled her over, her school T-shirt was covered in blood. I pulled up her top to give her CPR correctly," he said.
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The court also heard evidence from a neighbour who described hearing shouting next door.
Shalyna Chaplain said the shouting became "progressively louder".
"I became aware of a commotion, shouting next door," she told the jury. "It sounded like two teenage boys arguing. It was loud. It was shouting, but it was upset rather than aggressive. It was like two people shouting who were upset."
The court heard, through a written statement, that Miss Chaplain's partner, who had been working upstairs at the time, heard shouts of "no, no, no" in a "tone of disbelief".
The defendant denies murder, and an alternative charge of manslaughter.
The trial continues.
The prime minister announced on Monday that the new restrictions would come into force early next year to protect the "happiness of our children".
Speaking on the Electoral Dysfunction podcast, Ms Phillips said the move would have kept her in government.
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"This would've been enough to keep me in the tent," Ms Phillips said.
"Not only would it have been enough to keep me in the tent. I told them that. I was explicit about that.
"I spoke to various different people in Number 10 and really tried to push them to say, look, look, go for this. This is a bold move. This is bold and it is big and it is brave and it's the right thing to do."
Ms Phillips stepped down as safeguarding minister last month following Labour's dismal local election results, accusing Sir Keir of lacking the "drive to get anything done".
She also said restrictions on social media use should not "stop at kids".
"I don't think the algorithm should exist. Full stop," she said.
From next spring, under-16s will be banned from using all the main social media sites, including Instagram, Snapchat, YouTube, Facebook, and X - although messaging apps like WhatsApp won't be banned, and neither will educational sites like YouTube Kids.
Ministers are also looking at an overnight social media curfew for 16 and 17-year-olds, as well as banning infinite scrolling.
Starmer wants a 'legacy'
Ms Phillips also said Sir Keir had announced a ban "almost certainly" because he wanted to leave a "legacy".
She continued: "Men love [a] legacy, don't they?
"I cant give a toss about how I'm remembered, but here we are. But like, it was definitely the language we used to use to try and get things over the line. Like, this would be an amazing legacy."
Claire Freemantle was charged with two counts of causing death by dangerous driving and seven counts of causing serious injury by dangerous driving after the incident in Wimbledon, southwest London.
Schoolgirls Nuria Sajjad and Selena Lau, both eight, died in July 2023 when a Land Rover smashed through a fence at The Study Prep school, which was celebrating the last day of the summer term. More than a dozen people were also injured.
At Westminster Magistrates' Court on Tuesday, Freemantle, of Edge Hill, Wimbledon, was given permission to sit behind her lawyer, rather than in the dock, for the hearing.
She spoke to confirm her identity and was not asked to enter any pleas.
Defending barrister Sallie Bennett-Jenkins KC asked for Freemantle to be allowed to sit in the well of the court, rather than in the dock, due to concerns over her health.
Chief Magistrate Paul Goldspring sent the case to the Old Bailey for a further hearing on 14 July.
Freemantle was released on unconditional bail.
She is accused of killing Nuria and Selena, as well as causing serious injury to Nuria's mother Smera Chohan and another mother named Tamsyn Van De Vyver in the crash.
A third mother and her seven-month-old baby were also injured, as well as two eight-year-old girls and a seven-year-old girl.
Freemantle's lawyers have previously said she intends to plead not guilty to the charges.
The Metropolitan Police said in June 2024 that the driver of the vehicle in the crash had suffered an epileptic seizure and would face no criminal charges.
But after concerns were raised by the families of the two young girls a review of the case was carried out, and the force's Specialist Crime Command decided to reinvestigate.
Freemantle, 49, was arrested for the second time and released under investigation in January last year.
Operation Beaconport is examining cases between January 2010 and March 2025 where there are two or more suspects accused of sexual abuse and they are still alive; there is a victim of a sexual offence with physical contact; cases have not already been reviewed; and no further action had been taken.
In November, 1,273 such investigations from 23 police forces had already been referred to the National Crime Agency (NCA), 236 of which were prioritised because they involved allegations of rape.
On Tuesday, the NCA said: "At this early stage, the reviews have identified closed cases from eight force areas that may have viable lines of inquiry.
"The forces have been directed to reopen these cases, to determine the next steps in relation to any reinvestigation.
NCA director general Graeme Biggar said it was "the first step toward seeking justice for victims and survivors".
"Operation Beaconport is the most comprehensive and complex investigation into child sexual exploitation and abuse in UK history," he said.
The review of cases coincides with the one-year mark of the publication of Baroness Casey's national audit on group-based child sexual exploitation and abuse.
It made 12 recommendations which the government has accepted. Reflecting on that audit on Tuesday, the home secretary described it as "a landmark report, exposing more than a decade of inaction in the face of these appalling crimes".
Shabana Mahmood said: "Victims and survivors were, time after time, let down by the very institutions responsible for keeping them safe, despite repeated warnings and longstanding recommendations for action."
She added: "I remain determined that we confront these failings directly and decisively."
Ms Mahmood also confirmed that an independent inquiry into grooming gangs, chaired by Baroness Anne Longfield, will soon announce which local areas will face specific local investigations.
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The question of historical investigations into grooming gangs has also attracted the attention of Elon Musk, who accused Sir Keir Starmer of being "complicit" in the scandal.
The prime minister responded, accusing people of "spreading lies".
The home secretary also confirmed how the government was tackling cases where children, who were victims of exploitation, were treated as offenders and prosecuted.
Convictions and cautions for loitering or soliciting, for the purpose of prostitution, would be 'disregarded', with records of offences being deleted.
Acting chief constable Becky Riggs, the National Police Chiefs' Council (NPCC) lead for child protection and abuse investigation, said in a statement: "We know that for many victims and survivors, the harm they experienced was compounded by not being listened to or believed. That has had a lasting impact on trust and confidence.
"One year on from Baroness Casey's audit, our focus remains firmly on improving how we respond, ensuring victims and survivors are at the centre of every decision we make."
Restore Britain report
Meanwhile, the Rape Gang Inquiry, established and chaired by Restore Britain MP Rupert Lowe, published its full report on Tuesday.
The executive summary said the study set out to examine what it called "the systematic targeting of vulnerable girls, overwhelmingly White British, by predominantly Muslim Pakistani gangs" in the UK.
Among the key recommendations to tackle group-based child sexual exploitation are:
• Better support for victims of grooming gangs, their parents, and child witnesses providing evidence;
• Families placed at the centre of safeguarding; tougher sentences for perpetrators (and their deportation if they are a foreign national);
• Dedicated national units for prosecuting cases and repatriating victims who are trafficked abroad;
• A national compensation scheme for survivors;
• Legal reforms to improve child protection, restrict the activities of offenders and prohibit sharia marriages;
• Criminal penalties for officials, in certain circumstances, who fail to act against suspects.
Prince William became the first senior royal to enrol there in 1995, while Prince Harry attended from 1998.
It was a decision William and Kate long deliberated over, with reports they'd visited several schools before plumping for Eton, including co-ed Marlborough College, Kate's old school.
But there's one obvious advantage to Eton College - its location.
Just over the river from Windsor Castle, it's a short 15-minute drive from Forest Lodge, George's family home.
And of course his dad knows the school well.
Its handy location meant William often visited his grandmother for tea at Windsor while he was a pupil.
But the prestige of Eton has a hefty price tag. The annual fees would set you back £21,099.60 per term for 2025/26, set across three terms, according to the college's website.
Among the old boys, no less than 20 British prime ministers, from Sir Robert Walpole in the 1700s to David Cameron and Boris Johnson.
Other Old Etonians include George Orwell, Eddie Redmayne and Damian Lewis.
The college is steeped in archaic tradition, with the boys still wearing tailcoats.
George, 12, who made an appearance with his family at the Trooping the Colour ceremony at the weekend, is currently studying at Lambrook School, a private prep school in Berkshire, where he boards.
The school is also attended by his siblings, Princess Charlotte, 11, and eight-year-old Prince Louis.
The press were allowed to record William's first day at Eton with his parents, Charles and Diana, the then Prince and Princess of Wales, and brother Harry, with the family pictured as the young prince signed in on 6 September, 1995.
Five years later, aged 18, William was interviewed about his time at the school, and said: "I've really enjoyed being able to go about Eton as just another student."