Before the sun rose on Saturday, 10 February, the cracks of gunfire were already echoing.

Dr Amira al-Assouli was in Nasser hospital’s maternity building when she heard a man screaming the shahada, the Islamic declaration of faith, right below her window.

"There’s an injured man," people began shouting.

By the time she raced down the stairs and reached him, he was dead.

Ibrahim Salama had also heard the screams. He was staying in a shack on the hospital grounds and came out to see what was happening.

"Suddenly I felt something hot in my leg and I fell down," he says. "I was looking at my leg - it felt very heavy and I saw a lot of blood."

Dr Assouli again risked her life. Video filmed by an onlooker shows her taking off her jacket and running to him with her head low. "I didn’t hesitate," she told the BBC.

Ibrahim remembers Dr Assouli putting a hand on his chest and declaring: "He’s alive. He’s alive."

The BBC has spent several weeks establishing what happened at Nasser, one of Gaza’s biggest and busiest hospitals until an Israel Defense Forces (IDF) raid last month. On Tuesday, we revealed accusations from medical staff that they were detained, beaten and humiliated by IDF forces during the raid, prompting the UK government to call for answers from Israel. The US State Department said Israel has a "moral responsibility" to investigate credible reports of abuses or violations of humanitarian law.

Now, through witness testimony and analysis of verified video footage, we can show how the days leading up to the raid unfolded. Medics, patients and displaced civilians sheltering outside the main entrance described how they were trapped as anyone who tried to move around would be shot at.

The BBC has verified footage of 21 incidents of gunfire or its impact filmed from within the hospital grounds and has confirmed the shooting of three people there.

We shared our findings in detail with the IDF, along with questions about its operation at Nasser.

Israel has repeatedly accused Hamas fighters of using hospitals and medical centres as hiding places for weapons and command centres. It also says Hamas and other armed organisations have used Gaza’s hospitals to hide hostages taken from Israel on the 7 October attacks.

The IDF told the BBC there were "active fights in the area" in the days before its troops entered the hospital, and that "precise shots" had been fired at "terrorists identified in the vicinity".

Once inside, the IDF said, it found medicines that were intended for Israeli hostages as well as weapons. Hostages who were released during a brief truce in November have given accounts of being locked in rooms there.

Sharon Aloni Cunio has said she was taken to Nasser in an ambulance, disguised in traditional Arabic clothes, while her husband, who remains in Gaza, was put under a sheet to look like a corpse. The couple, with their two young children and other hostages, spent weeks in a small room on the hospital’s first floor, where stacked boxes separated the hostage section from other rooms, she said.

Others have given similar accounts of being held at the hospital, describing crying as they were locked in rooms there, having to knock on a door to be escorted to the toilet, and their terror at not knowing what would happen to them.

Those we spoke to in the hospital, including international medics who have stayed and worked there since the war began, say there was no overt presence of Hamas fighters they were aware of.

Following the raid, the IDF said some 200 terror suspects had been detained, including some who had "posed as medics".

In the days before the raid, the fear in Nasser was building, and almost everyone we spoke to who was in the hospital at this time believed IDF snipers and drones were targeting people moving between buildings on the hospital site or standing by windows.

"They surrounded the hospital with tanks, with bulldozers, quadcopters in the sky, snipers were everywhere," said 26-year-old Dr Mahmoud Shammala, an oral and maxillo-facial surgeon.

"We can’t stand by the window because if we stand by the window we’ll get shot in our heads or even chests or even shoulders. And also bombing is everywhere... It was very difficult times, especially in those last days."

People in the hospital grounds had little protection from gunfire.

"A lot of displaced people who were living in the complex were walking around normally and they got targeted," said Nasser doctor Mohammed Harara.

"It got to the point where we couldn’t reach these injured people. If you want to go to bring someone who’s injured inside, it’s like sacrificing or endangering yourself. A lot of people tried to go to save their brothers, relatives, anyone who they knew who was injured. They were targeted directly when they tried to reach them."

When asked about reports of shootings of people within Nasser, the IDF responded that it fired only "precise shots at terrorists" identified around the hospital complex.

On 8 February, a nurse, Hazim Abu Omar, was shot and wounded while on shift inside the operating department.

Multiple people the BBC spoke to referred to the incident, including two doctors who said they were in the room at the time.

Footage shared online by a Nasser doctor shows the injured nurse being rushed into an operating theatre on foot and appear to start to lose consciousness as colleagues struggle to cut away his blood-soaked clothing.

It is not possible to determine who fired the shot, and the IDF did not respond to requests for comment on this.

The same day, a video shows people in civilian clothing using an improvised pulley system to get water to a group of people gathered near the grounds of one of the three schools located near the hospital.

When a man attempts to get across the street, a loud gunshot can be heard. It does not strike him but the BBC’s assessment of the audio suggests it was fired close to where the video was filmed at the hospital’s north gate.

In other videos posted that day, the buzz of drones can be heard in the sky overhead as people move through the hospital grounds in fear.

Ibrahim Salama was shot in both legs when he went outside on 10 February to see who was screaming. The pain, he told the BBC, was unimaginable.

As he lay in the shack covered in blood, a doctor who was too scared to approach was calling to him and telling him to keep talking, trying to make sure he didn’t lose consciousness. Others stood frozen, filming videos and taking photos on their phones.

By the time Dr Assouli arrived at his side, Ibrahim had been lying there for about an hour. She and the other medics put him on a stretcher and rushed him inside the hospital

A video from the same day shows a man crawling along the ground as he tries to reach an injured or dead person lying just a few feet from the hospital grounds. The same body can be seen still lying there in a video posted a day later, suggesting no one felt it was safe enough to step out into that street to retrieve it.

"We can’t go from one building to another building. The snipers will shoot at anybody who would move in the hospital yard. Nobody can move outside of the buildings," Dr Mohammed Moghrabi said in a video posted on Instagram that day.

On 11 February, two separate pieces of footage emerged of a corpse lying on the ground between the main hospital building and the gate on to al-Dahra road.

Dr Harara said bodies could stay in these positions for four or five days, with cats and dogs "eating their flesh".

The BBC has verified footage of dead bodies left to rot on the ground, close to the gate. Cats can be seen crawling over the corpses.

The man with his arms raised was checking on a body next to the hospital gate

The chaos and confusion in Nasser escalated further on 13 February when a handcuffed man dressed in a white jumpsuit with a piece of yellow fabric tied around his head entered the complex with orders for people to leave.

He was identified to the BBC by people at the hospital as Jamal Abu al-Ola, a Palestinian man staying at the hospital who had disappeared a day earlier. The overalls he was wearing are the same as those worn by other men detained by the IDF.

Eyewitnesses said he entered the hospital three times that day, following a precise route, and with a drone overhead.

The second time, there appeared to be a cut on his face.

"He was speaking in an unnatural way. He was so scared from everything they [the IDF] were saying to him," Dr Harara told the BBC.

"His mum was there and at that time she told him ‘please come and stay with us, don’t go back for them’. He told her ‘I need to go back, I cannot stay.’ He said if he didn’t go back they would come inside and they would kill him and they would execute his family."

On the third occasion, as he left the hospital, eyewitnesses say he was shot dead.

"[He] was executed before our eyes. In front of the displaced and in front of his mother," one displaced person staying on the hospital grounds told the BBC.

Nobody the BBC spoke to saw where the bullet came from. The IDF did not respond to BBC questions about Jamal’s death, but has previously said that the "incident in question" was under review.

Doctors at Nasser reported more shootings within the hospital grounds on this day. Dr Khaled Serr posted on Instagram saying that two boys had been shot while playing, and in a voicenote from the time, shared with the BBC, he said three civilians were shot in front of the hospital gates. "One of them has a bullet inside his abdomen," he said.

Photos of each of the boys Dr Serr said were shot while playing match a video posted on the same day by a journalist who was in the complex at the time and verified by the BBC. We cannot independently confirm the circumstances of the shootings.

On the same day, a tank knocked down part of the wall surrounding the Nasser complex. Orders for people to leave were made over loudspeakers on Israeli military vehicles.

"Get out immediately... Those who would not get out risk their lives. All those that are inside the hospital, get out at once," a message blared in Arabic.

On 14 February, a drone circled above Nasser. A voice ordered everyone to leave. The Israeli raid was about to begin.

Ibrahim left on crutches. He describes seeing "bodies of people all around", some "being eaten by cats". As he left through an Israeli checkpoint, he says he saw many people around him being detained.

Outside the emergency department at Nasser, where thousands of displaced people had been camping before the raid in February

While Ibrahim had escaped, things at Nasser were only getting more intense.

In the early hours of 15 February, a shell hit the orthopaedic department, killing one person, according to the hospital’s general manager, Atef al-Hout.

In reference to its operation at Nasser, the IDF said a "stray shell" had been fired towards a military target nearby and had accidentally hit a building inside the hospital. However, it did not specify which building it was referring to.

A video shows the medics who had remained at the hospital pulling the injured from a room reduced to rubble.

And for those who chose to leave, the road was not safe.

The BBC has verified footage of Dr Harara among a group of people who came under fire just over 2km from the hospital as they headed south from Khan Younis towards the southern city of Rafah on 15 February.

He is seen shouting for help as he frantically applies a tourniquet to an injured woman’s leg.

In a later fragment of video, she is seen lying in the back of a car being driven away from the scene when another loud bang is heard.

In another video, a group of men - some of whom are wearing medical scrubs - flee when one steps into the street and comes under fire.

Back at Nasser hospital, a crack of gunfire can be heard on video before an injured man crawls back through a door in the emergency building. He is dragged away along the floor as blood gushes from his injury and he groans in pain.

Among those who remained at the hospital were patients who could not move, displaced people with nowhere to go, and medics who felt duty-bound to stay.

"Where could I evacuate with a diabetic husband who needs to have a bathroom next to him, and is on a walker. I cannot live in a tent or on the sand so I stayed," one woman told the BBC.

IDF

An IDF handout photo showing troops operating at Nasser hospital

During Israel’s takeover of the hospital, those who remained describe surviving on limited food and water, performing ablutions, or cleansing before prayers, using the fluid from medical drips and living in cramped and unsanitary conditions after being moved into a single building. They feared being shot if they returned to the yard.

The IDF has said its operations at Nasser were conducted in a "precise and focused manner, creating minimal damage to the hospital’s ongoing activity, and without harming the patients or the medical staff".

On 16 February, medics at the hospital were forced to strip and kneel with their hands behind their heads in front of the shack where Ibrahim had been shot almost a week earlier. Many were then detained.