A child plays among the ruins of a house in western Mosul that was destroyed in a March 17 coalition airstrike that killed more than 100 people. (Balint Szlanko/AP)

The last thing Ahmed Manhal discussed with his six cousins and nephews was what they were all going to cook for lunch the next day.

It was March 16. By 9 the next morning, the 22-year-old’s family members were dead, along with nearly 100 others sheltering in a three-story building in Mosul’s Jadidah neighborhood.

An investigation released Thursday by the Pentagon said that a U.S. bomb targeting two Islamic State snipers inadvertently triggered a cache of Islamic State explosives stored on the second floor of the structure. The resulting blast, the Pentagon said, killed most of the 101 civilians inside the building and four others in an adjoining house. The targets of the airstrike, the two snipers, were also killed.

[Pentagon confirms airstrike killed more than 100 civilians in Mosul, blames ISIS explosives]

Manhal, who lives across the street from the destroyed house, heard the explosion, as did his father, Sameer. The two deny that the Islamic State moved any explosives into the building, however. Both recalled militants arriving the night before the airstrike, telling those still in their homes to leave before fighting began the next day. The snipers, they said, arrived at the house for the first time the morning of March 17, armed with rifles and little else.

“It was an airstrike,” Manhal’s father said of the incident. “There were no explosives.”

Brig. Gen Mohammed al-Jawari, the civil defense chief for Mosul, also disputed the U.S. report.

“We were the first people who went to the site and evacuated all the bodies, and we didn’t find any explosives there, only a few grenades and IEDs that weren’t exploded. . . . What caused that destruction was an airstrike, nothing else,” he said.

The elder Manhal said civilians from the neighborhood had been sheltering at the house for a week before the strike, taking advantage of its basement — the only one on the block — for protection.

In its report, the Pentagon said U.S. and Iraqi forces believed that the structure was empty of civilians, having watched the Islamic State evict families from homes in the days before the strike.

The U.S. Central Command, however, was made aware that there were families trapped in the area on March 14, three days before the airstrike, according to direct messages sent to its official Arabic twitter account. The sender did not wish to be identified for security reasons. In a message, he requested the urgent evacuation of families trapped inside houses near the Fathi al-Ali mosque, saying they were at risk of being killed. The house hit in the U.S.-led strike was about 1,500 feet away from the mosque.

“Information received,” Central Command replied. “Thank you for your message.”

[Airstrikes on Islamic State-held town in Syria kill scores of civilians, monitoring group says]

Ahmed Abdulkareem, 32, was next door when the bomb, a 500-pound, satellite-guided munition called a GBU-38, penetrated his neighbor’s roof. The weapon was set with a delayed fuse, the Pentagon’s report says, so that the bomb would explode after it entered the house. The delayed detonation ensured that the ensuing blast would be contained on the second floor, killing the snipers firing from that level.

Instead, the Pentagon said, the bomb triggered additional explosives stored in the building, producing “a powerful blast and overpressure that triggered a rapid progressive failure of the structure.”

Abdulkareem’s brother was killed in the explosion, despite being next door. He, too, said that there were no Islamic State explosives stored in the structure.

“There were only families,” he said.

The Pentagon’s report said that the bomb’s blast should have resulted in “no more than 16-20% damage to the structure, localized to the front of the second floor.” The additional explosives, the report says, razed the structure. A crater found at the rear of the building, presumably caused by the militants’ munitions, indicated that the additional explosives “contained more than four times the net explosive weight of the GBU-38.”

A U.S. military pilot, who spoke on the condition anonymity because of his active duty status, said the report’s damage estimates for the initial airstrike were low and unrealistic. The pilot, who flew hundreds of combat sorties over Iraq and Afghanistan, said that using a GBU-type bomb on a residential structure ensures that there is an “extremely high probability” that the “entire building will be destroyed and every living entity inside would be killed.”

The U.S.-led coalition has acknowledged killing more than 300 civilians since it started its air campaign against the Islamic State in 2014. Monitoring groups, however, put the number of civilian dead caused by errant airstrikes in Iraq and Syria in the thousands.

“Americans have technology that they can see anything; sometimes they shoot one man from the air,” the elder Manhal said. “They did this on purpose.”

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