As my colleague Alex Emmons reported last month, Syrian activists and first responders accused the United States of killing dozens of civilians in an airstrike that mistakenly targeted a mosque in the rebel-held village of al-Jinah on the evening of March 16.

As evidence, Davis provided an aerial photograph of the building destroyed in the attack, identified by U.S. officials as a “partially constructed community meeting hall.”

Confronted with these claims, a Pentagon spokesman, Navy Captain Jeff Davis, told The Intercept that they were mistaken. “The area was extensively surveilled prior to the strike in order to minimize civilian casualties,” Davis said. “We deliberately did not target the mosque.”

The rights group’s report was one of three parallel investigations into the U.S. strike on al-Jinah released this week by investigators who specialize in the painstaking analysis of social media evidence of potential war crimes.

But, as Human Rights Watch reported this week, witnesses in al-Jinah said that the building destroyed by two armed, Reaper drones firing Hellfire missiles was the newly built Omar Ibn al-Khatab mosque, where about 300 civilians had gathered for the Muslim night prayer. At least 38 people were killed in the attack, which included the dropping of a 500-pound bomb.

“The mosque in the left edge of the photo was not targeted,” Davis stressed in a briefing for reporters the next day. “Military officials believe dozens of al-Qaida terrorist leaders were killed in the strike.”

The Bellingcat researchers point out that video, “recorded during the construction of the mosque and published on YouTube in November 2014 ,” appears to confirm that the rooms destroyed in the attack included the mosque’s ritual wash room, toilets, Winter prayer hall and the kitchen.

In addition to the testimony of 14 witnesses who spoke to Human Rights Watch, video and photographs shared online , compiled by open-source analysts at Bellingcat, provide compelling evidence that the building was indeed a mosque.

But perhaps the most convincing case that the U.S. bombing was a deadly error is a richly detailed video report on the strike produced by Forensic Architecture , a research agency, based at Goldsmiths, University of London, led by the Israeli architect Eyal Weizman.

Weizman’s architectural detectives, who have previously investigated potential war crimes in Syria — as well as in Israel, the West Bank, Gaza, Pakistan and Guatemala — produced a model of the building based on images of it before and after the strike, combined with interviews with survivors, first responders and the building’s contractor.

Images of the building featured in the Forensic Architecture report show distinctive features, like a megaphone for the call to prayer, prayer rugs, and a clearly defined mihrab — a semicircular niche in the wall of a mosque that indicates the direction of Mecca — indicating that it was a mosque.

“The architectural reconstruction has also allowed us to understand the sequence of events that took place in and around the mosque following the strike,” the Forensic Architecture investigators explained on their website.

The strike began when two bombs completely demolished the northern part of the building. The layout of the rubble in the deep craters is consistent with ground penetrating bombs. In order to escape, worshippers in the main prayer hall in the south part of the building had to climb over the rubble that partially blocked the doorways and passageways and destroyed the stairs. While people exited the building and immediately afterwards they were targeted by further missile strikes. Examining images of munitions remains, Chris Cobb-Smith (who assists Forensic Architecture on weapon analysis), Bellingcat, and HRW’s experts identified the munitions fired outside the mosque as likely to be Hellfire missiles. This is consistent with an anonymous US official who, when speaking to the Washington Post, confirmed that “the attack involved two Reaper drones, which fired more than four Hellfire missiles and dropped at least one 500-pound guided bomb in a follow-up strike.”

To U.S. drone operators, the fleeing survivors cut down as they rushed from the mosque perhaps looked identical to the Qaeda militants they thought they were attacking. But, as Human Rights Watch observed, that mistaken impression suggests that their intelligence on the targeted area was woefully inadequate.

“While the U.S. authorities appear to have fundamentally misunderstood the nature of the building they attacked, they also appear to have inadequately understood the pattern of life in the area,” the rights group argued.

A U.S. official said that the attack happened after evening prayer had concluded, implying that civilians had left the area. While it is not clear which prayer the official referred to, U.S. statements about when the attack happened and information from those present at the mosque show that the attack happened at about 6:55 p.m., just 15 minutes before night prayer on that day. The fact that the night time prayer was about to begin is relevant even if U.S. authorities believed that the targeted building was a community hall since they knew that a mosque was nearby. Information about prayer times is easily accessible online and should have been well known by US authorities. Local residents also said that it was well known in the area that the religious group in charge of the mosque was holding religious lectures in the targeted building every Thursday between sunset prayer and evening prayer, around the time of the attack. Any attempt to gather pattern of life information about the targeted building from people with local knowledge might also have alerted US authorities to this fact.

“The U.S. seems to have gotten several things fundamentally wrong in this attack, and dozens of civilians paid the price,” Ole Solvang, the deputy emergencies director at Human Rights Watch, said in a statement.

According to the Pentagon’s own data, the U.S.-led coalition bombing Syria and Iraq has killed between 102 and 396 civilians in 18,645 strikes from August 2014 to the end of February. The three new reports on the bombing of al-Jinah suggest that the actual number of civilians killed in American bombing could be far higher.