Fear plagued Saleh Mohammed al-Hila, 37, on that Sunday.

“I was lying on the ground of the tent and told my son ‘May God save us from this night,’” he recalled.

Hamas had launched rockets at central Israel hours earlier, setting off air-raid sirens in the Tel Aviv area for the first time in months. Israel’s military said the barrage had been fired from Rafah — the city in southern Gaza where Israeli forces were advancing and Mr. al-Hila was sheltering with his family in a camp for displaced people.

Israel was sure to retaliate, he thought. And it did — Israel’s military fired back and said it had destroyed the launcher used in the rocket volley, which was not near the camp.

But a few hours later, Israel struck again, dropping two 250-pound bombs on temporary structures in the camp. Lethal shrapnel hurtled in every direction and soon a fire was raging. By morning, dozens of Palestinians had been killed, including four of Mr. al-Hila’s relatives.

International outrage followed the second May 26 attack. Prime Minister Benjamin Netanyahu, who usually rejects criticism of Israel’s warfare, called the killing of civilians a “tragic accident.” Rear Adm. Daniel Hagari, the Israeli military spokesman, said there were “no tents in the immediate vicinity” of the targets. Israel said it had taken great care to avoid civilian harm, despite Hamas militants’ practice of operating among civilian centers, and that it would open an investigation into the strike.

The New York Times spoke with multiple witnesses and munitions experts, reviewed videos of the scene and analyzed satellite imagery to piece together a clearer picture of the strike.

Maj. Nir Dinar, an Israeli military spokesman, told The Times that Israeli forces were not aware that the compound targeted was in a place serving displaced people.

But the Times investigation found that Israel bombed targets inside a camp that had existed for months, sheltering hundreds of people displaced by the war. The analysis raises questions about an assessment the Israeli military said it made before launching the strike that it was unlikely to harm civilians.

Against the Backdrop of a Military Offensive

Ahead of Israel’s operation in Rafah, which began on May 6, the military had issued evacuation orders for neighborhoods east of the city center, but not the area that included this camp, which had housed up to 350 families.

The camp, Kuwaiti Al-Salam Camp 1, was created several months ago, near the Tal al-Sultan area of northwestern Rafah. It eventually grew to include dozens of tents and about 40 long metal sheds with wooden frames, videos and satellite imagery show. Each shed typically housed five to seven people, according to one of the charities that built the camp, though it is unclear how many people were in any of the sheds during the Israeli strike.

Mr. al-Hila got a tent there for his family in March. His mother and sister settled into another. By that point, the family had been displaced four times.

On May 26, Mr. al-Hila and his 6-year-old daughter, Rehab, had been in his mother’s tent, but he went back to his own for evening prayers. His mother had asked him to return with her other grandchild, 2-year-old Mostafa. Her walker was broken; she was waiting for a new one.

Around that time, Israeli jets were closing in. Their targets, the Israeli military later said, were Khaled al-Najjar and Yassin Rabia, Hamas officials accused of orchestrating attacks against Israelis. The Israeli military said the two were holding meetings in two of the camp’s sheds.

The jets released two American-made GBU-39 “small diameter” bombs, each weighing about 250 pounds and carrying 37 pounds of explosive. The GPS-guided bombs have wings and tail fins that pop out once they are dropped, allowing them to glide long distances and steer to their targets. The maker, Boeing, bills the GBU-39 as a “low collateral damage” precision weapon.

Israel had come under intense criticism for using heavy munitions in populated areas, accused of causing indiscriminate casualties and destruction. After extensively using 2,000-pound bombs, each with 945 pounds of explosive, the Israeli military shifted to smaller, more targeted attacks.

Using bombs the size of the GBU-39 would be “certainly indicative of an effort to be discreet and targeted and precise,” said John F. Kirby, a White House spokesman.

But in this strike, the combination of weapon, location and timing caused destruction well beyond the target. The explosions blasted the bombs’ steel casing into shards that could cause death and injury up to around 570 feet away. And they detonated in corrugated metal structures with the potential to create far more shrapnel.

The sheds that were targeted stood within a few yards of several others, as well as parked vehicles. Israeli military drone video analyzed by The Times appears to show at least four people walking nearby when the bombs exploded.

Two videos posted to social media captured the moment of the strike, with metadata from the videos suggesting it occurred at 8:47 p.m.

Two minutes later, footage filmed from afar revealed large flames. Billowing clouds of smoke rose into the orange-tinged night sky within minutes, as the sound of Israeli drones hummed in the air.

The two targeted sheds and the two closest to them were obliterated, an analysis of satellite imagery from the next day shows. Where a row of 11 sheds had stood, seven remained, next to about 6,000 square feet of blackened earth.

Farther away, several other sheds appear to show blast damage, with pieces apparently missing that were there a day earlier.

Chaos and Carnage

Video shot by witnesses immediately after the strike captured the chaos: people running and screaming, pulling charred bodies from flaming wreckage, clambering over twisted metal as they tried to save the living. A man held up the headless body of a small child.

Witnesses said tents near the area of the blast were no match for the shrapnel that rocketed outward.

Mohammed Khalil Qannan and his family were finishing dinner when his wife, Nedaa, grabbed a yellow jug to fetch water for tea. As she reached the entrance to their tent, he said, “I just heard two heavy strikes and saw a giant red light with smoke up over the whole dark area.”

Ms. Qannan screamed “My leg! My leg!” and collapsed, unconscious, her legs shredded by shrapnel, as cries from tents around them filled the air. Their eldest son, Khalil, rushed to help her, Mr. Qannan said, but he, himself, panicked.

“I just went out of the tent screaming unconsciously asking relatives and people around to come and save my wife,” he said.

Gravely wounded, Ms. Qannan was eventually loaded into a small yellow bus, along with other broken bodies, living and dead, Mr. Qannan said.

Mohammed Abu Helal, a doctor at the European Gaza Hospital, was at home preparing a dinner of canned tuna and beans when he saw a flash “that lit up the entire area” and heard booms. He rushed to the scene, about 100 yards away, where he treated the wounded as the smell of “burned flesh” filled his nose.

“There were critical conditions, charred bodies, dismembered bodies, and amputation injuries and wounds,” he explained.

At first, the raging fire provided the only light. Rescue workers and ambulances arrived within about 15 minutes, according to footage verified by The Times. Their red and blue flashing lights cut through the darkness, and Dr. Abu Helal said they did as much as they could with what supplies they had.

The ambulances were low on bandages, he said, so they used torn clothing in some cases and tried to triage the patients.

“This guy is alive, hurry up, bring an oxygen tank,” he recalled telling the medics. Or, “This guy has no hope of surviving, leave him and move to the next.”

The Palestine Red Crescent said at 10:01 p.m. that its ambulance crews were transporting “a large number” of dead and wounded from an Israeli strike in Rafah.

At 10:48 p.m., Gaza’s health ministry said only that a “large number” of deaths and injuries had been reported.

What Israel Said

As grisly images from the strike spread on news sites and social media, there was no comment for hours from the Israeli military. When a statement came, it did little to clear up the initial fog of war.

Around midnight, the military said that it had struck a Hamas compound using “precise munitions and on the basis of precise intelligence that indicated Hamas’ use of the area.” It was “aware of reports indicating that as a result of the strike and fire that was ignited several civilians in the area were harmed,” its statement added, saying that the “incident is under review.”

An hour later, a new statement named the two dead Hamas commanders and detailed the accusations against them.

As morning came, families searched for their loved ones in clinics, hospitals and the wreckage. Video showed flattened structures and burned-out cars at the scene. Children dug through the debris, searching for anything salvageable: scattered pasta, burned dates, tiles and bent metal.

And the toll climbed: 45 killed and 249 injured, Gaza’s health ministry said that afternoon.

Mr. al-Hila was struggling to sleep — or even speak.

His mother, who had asked him to return with her grandson, was dead. So were his sister, his 15-year-old niece and his 1-year-old nephew. The boy’s body was unrecognizable; a brother helped identify him from the gray of his trousers.

“I feel I am dying and having a nightmare I cannot forget or get out of,” he said.

Mr. Netanyahu offered his first comments on the attack around 6:30 p.m. on Monday — nearly 22 hours after the strike and blaze. He told the Israeli Parliament that “despite our supreme effort not to harm uninvolved civilians, a tragic accident occurred to our regret last night.” And he said, as he often has, that Hamas embeds in the civilian population to ensure innocent casualties.

Ghazi Hamad, a senior Hamas official, has said that the group tries to keep Palestinian civilians out of harm’s way. But Hamas has taken advantage of the urban areas in Gaza to provide its fighters and weapons infrastructure with an extra layer of protection, running tunnels under neighborhoods, launching rockets near civilian homes and holding hostages in city centers.

With international calls for accountability growing, Admiral Hagari said on Tuesday that the bombs were “the smallest munition that our jets can use.” That is true, though some Israeli drones can carry smaller explosives.

Though he said there were “no tents in the immediate vicinity” of the targets, satellite imagery from the same day shows more than 60 tents and other makeshift structures within 500 feet, inside the range given by U.S. military reference guides for risk of death or serious injury.

Admiral Hagari also stressed that the strike did not hit either a nearby U.N. compound or an Israeli-designated “humanitarian area” for people fleeing the city, as some initial reports had claimed, without acknowledging the displaced persons’ camp.

The Times’s analysis shows that the site targeted was within the borders of the camp, and suggested Israel had failed to take adequate care to safeguard civilians. The camp was well-known, the metal sheds were spaced just over a meter apart, and there were tents in the area.

Satellite imagery and videos show the first of the metal shelters, roughly 48 feet long, including those that were bombed, had been erected nearly five months earlier. One of the organizations that ran the facility, Al-Salam Association for Humanitarian and Charitable Works, confirmed that the structures were part of the camp.

The association said that Israeli authorities were aware of the camp, and had been consulted in choosing its site. Major Dinar said the Al-Salam organization had not coordinated the establishment of its camp via the Rafah municipality. He denied the area was “defined” as a displaced persons’ camp or a humanitarian zone.

Admiral Hagari has said that Israel engaged in aerial surveillance to avoid civilian casualties, and even delayed the strike on that basis. But Major Dinar said that if people were there, “it is because Hamas took them there and hid behind them.” And he declined to discuss the decision-making process behind the strike in detail, saying it was being probed by a military commission charged with looking into allegations of wartime misconduct.

The Israeli military also referred questions to COGAT, an Israeli agency dealing with the Palestinian territories, which did not respond.

To support the contention that Hamas operated in the area, Admiral Hagari showed surveillance imagery of a battery of rocket launching tubes, partly embedded in the earth, about 140 feet from the target. Hamas had fired toward Israel from there on Oct. 7, he said. The tubes were still there, intact, when The Times visited the site after the strike on May 26.

The Israeli military’s top legal official, Maj. Gen. Yifat Tomer-Yerushalmi, called the strike in Rafah “very serious” and told a conference that it would be investigated “to the fullest extent.” The military, she added, “regrets all harm to noncombatants during the war.”

The Cause and Effect of the Fire

Among the biggest unanswered questions are how people were killed and injured — by the blast or by the fire — and what set fire to the sheds.

Admiral Hagari appeared to blame the deaths on the blaze alone.

“We are investigating what caused the fire that resulted in this tragic loss of life,” he said, stating that Israel’s weapons alone could not have ignited such a large blaze.

One possibility, he said, was that weapons “which we did not know of” might have been stored nearby and detonated. The Israeli military, he said, was assessing social media videos “which appear to show secondary explosions.”

It is not clear what videos he meant. The Times has reviewed dozens of videos and has been unable to find any that suggest a significant secondary explosion.

Admiral Hagari called the fire “unexpected and unintended,” but aid workers and others note that displaced people in a camp have cooking fires, and often have camp stoves with tanks of flammable — potentially explosive — cooking gas.

At least two gas canisters are visible in footage recorded at the scene the day after the strike, a detail first reported by the French newspaper Le Monde, and confirmed by The Times.

For Mr. Qannan and his family, another painful chapter with a lot of unknowns awaits.

“I am not feeling any safer in this place,” he said. “I will pack everything and leave this area.”