The young witness is now describing George Floyd's last moments in graphic detail.

"He stopped being vocal and he was struggling to breathe," she says.

"I could see he was going unconscious and his eyes were rolling to the back of his head."

At this point in the trial, bystander video of Floyd's final moments is being replayed multiple times.

They can be heard begging the officers to "check his pulse" and repeatedly saying "he's not moving".

The witness is heard among them, saying "it's been over a minute".

Asked about those moments, she recalls that she feared he was going to die and, after a certain point she "kind of knew".

"He was just laying there, no longer fighting or resisting," she says.

Image source, Getty Images

Let's step back for a moment from the courtroom to ask what is at stake in this high profile case and why it matters.

Video footage of Derek Chauvin kneeling on George Floyd's neck last May was replayed the world over.

To many, Floyd's death while in police custody became a lucid symbol of police misuse of force - particularly against people of colour - and it incited worldwide demonstrations for racial justice.

But Derek Chauvin's fate at trial is not sealed. In the US, police are rarely convicted for deaths that occur while they are on duty, if they are charged at all.

The verdict in this case will be widely seen as an indication of how the US legal system treats deaths that occur while in police custody.

Image source, Court TV

The witness is emotional and sounds like she is fighting back tears.

She describes a sense of helplessness, saying "It was difficult because I felt like there was nothing I could do."

As a bystander, she "felt like I was failing to do anything."

The prosecutor questions her on the reactions of other bystanders, many of whom asked officers on the scene to check George Floyd's body for a pulse.

She says the officers did not, and that Chauvin's knee "remained on him the entire time till paramedics came," referring to Floyd.

She adds that Chauvin seemed to drive his knee downwards in a manner that put more weight onto Floyd's neck as well.

"I saw his back foot lift off the ground and his hands go into his pocket, she says. "I saw his knee move down into Mr Floyd's neck."

Joshua Nevett
Journalist, BBC World Online

Image source, Getty Images

In court today we've heard from several eyewitnesses to George Floyd's arrest - including three minors.

By the time one of those witnesses, then 17-year-old Darnella, started recording last May, George Floyd was already gasping for air, begging, repeatedly, "please, please, please".

At that point, Darnella could never have imagined the chain of events that her video would set in motion. At the click of a button, the teen spurred wave after wave of protests, not only in the US but across the world.

Her lawyer told the BBC she was traumatised by what she saw outside Cup Foods on 25 May. It was "the most awful thing she's ever seen", he said.

And testifying in court today, Darnella was audibly emotional recounting the events of that day.

She's not alone - several witnesses to violent encounters pay an emotional toll.

Read more about those who bear witness to these encounters.

The witness is among those who were on the scene and recorded George Floyd's arrest as it was taking place.

Describing how Floyd was behaving, she said: "I heard him say he couldn't breathe, and that his stomach hurt, and that he wanted his mom."

She went on to say "I knew initially something was wrong. A lot of people looked in distress."

The witness is referring to Floyd and Chauvin by their first names, as George and Derek.

"George was in distress," she said.

Image source, Reuters

The witness being questioned is talking about what she saw, including that other officers were there besides Chauvin.

In the footage of George Floyd's death played by prosecutors, other officers were seen keeping bystanders back as Derek Chauvin knelt on Floyd's neck.

So what is happening to them?

The three other officers involved with Floyd’s death are J Alexander Kueng, Tou Thao and Thomas Lane. Each is facing two charges of aiding and abetting second-degree unintentional murder and manslaughter.

Their fates in part rest with Chauvin’s, for if prosecutors can’t convict Chauvin, the case against the other officers will become harder to prove as well.

The prosecution has now called its fourth witness for today and its sixth overall.

It is another minor who was an eyewitness of George Floyd's arrest, so she will not be shown on screen.

She is a 12th grader who lives in Minneapolis and visited the Cup Foods corner store to purchase an aux cord to play music when she came upon the scene of the Floyd arrest.

The lunch recess has ended and members of the jury are back in their seats.

The afternoon session of Day Two begins now.

Tara McKelvey
BBC News, Minneapolis

On the opening day of the trial yesterday, one of the witnesses, Jena Scurry, a police dispatcher, described how she told a supervisor about Chauvin, and the way he was holding Floyd to the ground.

Prosecutor Jerry Blackwell said she “called the police on the police”.

Here in Minneapolis, people have been talking about city workers such as Scurry, and others who are responsible for protecting people and their property.

Many businesses near the courthouse have closed, because of the pandemic but also because of the trial.

Some worry about security, and have heard about threats.

But others say they still have faith in the police.

Sarah Quigley, a childcare worker, says her purse was stolen a while back, with her work ID. She went home, devastated, but the next day an officer knocked on her door. He had her purse, and said they arrested the thief.

The officer, she says, “seemed very happy to give me my stuff. He said: ‘know you need this for work.’”

She says not all the officers she had met have been as helpful - “it’s 50/50” - but he made an impression, one that stayed: “I guess it was kind of like, good karma.”

Image source, Reuters

Cameras are not normally permitted in federal courtrooms, which is why sketches of court proceedings are so common in high-profile US trials.

Due to Covid restrictions, the court sketch artist assigned to the Chauvin case is forced to watch from a video feed, much like the rest of us.

Here's how the trial looks through the eyes of an artist.

Image source, Reuters

Image source, Reuters

Image source, Reuters

Image source, Reuters

The prosecution team that represents the state of Minnesota in this trial is expected to argue its case over the next two weeks.

That means defence attorneys for former officer Derek Chauvin will likely start making their case on Monday 12 April, unless prosecutors finish sooner than expected.

Eric Nelson - lead attorney for the defence team - has already given us some indication of how his team will argue on behalf of Chauvin.

In his opening statement yesterday, he said that his client's use of force in the incident with George Floyd was "unattractive but necessary", and that Chauvin was simply following his training.

The defence team is sure to point out that there were no signs of asphyxiation or bruising on Floyd's neck, according to one autopsy, and will also suggest Floyd's pre-existing health issues and his drug consumption were the main contributing factors to his death.

Minneapolis police officers, medical personnel and emergency dispatch workers are likely to be on the defence's witness list.

You can watch part of yesterday's opening statements below:

If you're watching live you'll have heard Judge Cahill call several "sidebars" - summoning lawyers from both sides to confer privately, so that the media and others in the courtroom can't hear.

And, importantly, the jury can't heard these discussions, which often involve the judge's rulings on the evidence and questions that can be allowed in court.

In non-Covid times, this might be a physical sidebar, where lawyers from both sides approach the judge's bench. But due to Covid limitations, lawyers and the judge are speaking over the phone to each other from across the room.

"Sorry the technical difficulties are sending shooting pains into all our ears," the judge says after removing a headset at one point due to feedback.

Image source, Getty Images

The length of time Derek Chauvin knelt on the neck of George Floyd has become a symbolic part of the story.

An initial complaint against former officer Chauvin by the Hennepin County Attorney's office counted eight minutes and 46 seconds.

That's the time protesters have associated with Floyd's death, often kneeling for that period of time in observance of his passing.

The black stand-up comic Dave Chappelle even titled his first special after the Floyd death '8:46'.

Timestamps from the complaint document later corrected the time to seven minutes and 46 seconds.

At Mr Chauvin's trial so far, prosecutors have said the actual time Floyd spent under Chauvin's neck was over nine minutes - more than a minute longer than the initial complaint.

Police body camera footage of the incident confirms that to be true, which means the verified period of time is nine minutes and 29 seconds.

As we have already seen, prosecutors are homing in on that timeframe in much of their questioning.

Samantha Granville
BBC News, Minneapolis

Image source, BBC graphic

There’s nothing normal about Derek Chauvin’s trial.

It is being broadcast on television - a first in Minnesota state history - because of coronavirus safety precautions that prevent too many people from being in the courtroom and due to wide interest in the case.

If you walk in the front door and look to your right you would see jurors spaced about six feet apart. The normal jury box was replaced with office chairs and one-person desks.

Straight in front of you is where the judge sits, and he’s encased in plexiglass. To the left of the judge is the witness box, also in plexiglass.

On the left side of the room, there are multiple lawyers from each side. Only a few can fit in the courtroom because of Covid-19 restrictions.

In the back of the room, there are two journalists who are allowed to be there and cover the proceedings, with one camera broadcasting the trial to the world. The normal spectator gallery was also taken away.

Gary O'Donoghue
BBC News, Minneapolis

The young woman who shot that video is at the centre of this whole trial.

She only turned 18 last week.

Darnella was asked about what she saw as she walked from her home with her cousin to the Cup Foods store, by which time George Floyd was being restrained by those officers.

And you heard a her voice, incredibly emotional, cracking as she testified.

She was breathing quite hard at various points. Floyd's arrest clearly still has an enormous impact on her.

You heard her say she didn't want her cousin - who was nine years old, to see what was going on, because it "terrified and scared her".

Bear in mind this is part of the defence case. The officers on the scene allegedly felt threatened by those who were there.

That's why you heard the defence attorney, Eric Nelson, questioning MMA fighter and witness Donald Williams.

The questioning was particularly about the numbers of times he yelled out and the kinds of things he yelled at the officers, including curses and expletives.

Nelson was clearly trying to establish that this group of people - these bystanders - were threatening to police.

Image source, Getty Images

And that is a big battleground here, to what extent the officers were threatened by this group of people.

The prosecution is coming back time and time again, to ask whether there was any violence from the bystanders - whether they were really a threat.

Darnella was asked the same questions and said, "No, that there was nothing like that from them whatsoever."

It's incredibly tense in there at the moment. You can feel it across the city.

Speaking to prosecutor Jerry Blackwell, the 9-year-old witness described what she saw on the night George Floy died.

"I saw that officer put a knee on the neck of George Floyd," she says in response to questions.

We can't see the witness but we can hear how young she is.

Blackwell asks her if she sees that officer - Chauvin - in court.

"No," she replies.

Chauvin stands and removes his mask so that the witness is able to identify him.

Later, she says that Chauvin did not remove his knee until the "ambulance people" arrived.

"They asked him nicely to get off," she says, but Chauvin did not move.

Blackwell asks her how she felt watching Floyd be arrested.

"I was sad and kind of mad," she says. "It sounded like he was hurting."

Earlier, 18-year-old Darnella told prosecutor Jerry Blackwell that she has social anxiety, and doesn't typically speak up like she did when she came across George Floyd being held by police.

Blackwell asks Darnella how witnessing Floyd's arrest has changed her life.

“When I look at George Floyd I look at my dad, I look at my brother, my cousins, my uncles – because they are all black," she says, audibly crying. “And I look at how that could have been one of them.”

“I stay up apologising to George Floyd for not doing more."

“It’s not what I should have done – it’s what he should have done,” presumably referring to Derek Chauvin.

The defence chose not to question the nine-year-old witness after the prosecution finished.

This means the morning session has now ended.

The trial resumes at 13:15 local time (19:15 BST).

Image source, Court TV

The day's third witness has just taken the stand.

This is the nine-year-old girl who went to the Cup Foods store with her teen cousin Darnella, who just testified. The pair witnessed George Floyd's arrest.

She has arrived in the courtroom with a handler.

She will also not appear on camera because she is a minor.

Speaking to Darnella, defence attorney Eric Nelson is working to set the scene on the night that George Floyd died.

Through an extended series of questioning, Nelson asks Darnella if the road where officers held Floyd was busy, and if the crowd of bystanders grew over time.

He then asks Darnella if she was aware of all four of the police officers present that day.

No, she says, only of two - Officer Chauvin and Officer Thao.

"You couldn’t necessarily hear if those other officers were speaking to Mr Chauvin,” Nelson says - suggesting that the two unseen officers could have been communicating with Chauvin.

"As time went on, the crowd got louder?" asks Nelson.

"Yes, as he [Floyd] became more unresponsive," Darnella replies.