More than a week after the deadly explosion outside the Al-Ahli Baptist Hospital in the Gaza Strip, many questions remain unanswered about what exactly happened and who is responsible. And, as usual, there's been a lot of disinformation surrounding such a sensitive issue.

Many news organizations and independent investigation teams have questioned the narratives presented by both sides and have tried to conduct their own investigations, revealing some new details about the explosion. 

With limited access to the explosion site, and new information emerging every day, DW looked into some of the findings to help shed light on the events of that night.

Evidence, however, remains in many cases inconclusive. Several foreign leaders, including German Chancellor Olaf Scholz and French President Emmanuel Macron, have called for the incidents to be thoroughly investigated. And the United Nations has also said there is a "clear need" for an independent investigation. 

What is clear is that the blast has become one of the most contested events in the war between Israel and Hamas so far. Israel has been launching airstrikes on Gaza since the militant Islamist Hamas, a terrorist organization identified as such by the European Union, the United States, Germany and many other countries, carried out widespread terrorist attacks on Israel on October 7.

More than 1,400 Israelis have been killed, most in the initial surprise attacks. At least 7,000 people have been killed in Gaza in Israeli strikes in the last three weeks, according to the Hamas-run Health Ministry.

Due to these heightened tensions, some of the experts contacted by DW preferred not to comment further or openly on the issue.

What happened on October 17? 

The explosion occurred in the courtyard of the Al-Ahli Baptist Hospital in the center of Gaza City at around 7 p.m. local time on October 17. According to its operators, it is the only Christian-run hospital in the Gaza Strip.

There is evidence of the location and timing of the attack. A 20-second video which circulated on various social media platforms claiming to show the blast was the first significant piece of visual evidence to emerge. It starts with the whistling sound of an incoming projectile, followed by an explosion and a huge fire.

The blast killed a large number of people, but the exact toll remains unverified and difficult to confirm at a time when it's challenging for investigators to access the site.

The Hamas-run Health Ministry in Gaza said 471 people had died, but the Israel Defense Forces (IDF) said this figure was exaggerated and has not released an estimate themselves. American officials, meanwhile, have suggested the number was between 100 to 300 people.

Who is responsible for the blast?

Hamas immediately blamed Israel for the rocket strike. Israel rejected any responsibility and instead indicated the cause was a failed rocket launch by the militant group Palestinian Islamic Jihad, which in turn denied it. Several Western governments, such as the US intelligence said this week they had "high confidence" that the explosion was not caused by Israel, but by a Palestinian rocket that broke up mid-flight.

Several Western governments, such as  the UK, France or Canada, have also all said that their analyses showed the explosion had not been caused by an Israeli missile, but was likely the result of a rocket fired from within Gaza. 

What has been checked so far and how?

Neither hospital representatives nor Hamas authorities have so far presented any evidence of an Israeli rocket.

While it remains dangerous for independent investigators to access the area around the hospital, several news organizations and investigative groups have begun to carry out their own research to help provide more clarity. 

Some have looked at images of the crater to determine the direction and type of rocket used. Others have looked at the visual evidence in video clips, and there is also an analysis of the sound in the recordings of the rocket attack, as well as other evidence presented in this case.

Let's go through the findings one by one.

Forensic audio and sound analysis

On October 20, UK's Channel 4 published audio and photographic analysis by NGOs specializing in human rights' investigations that have cast doubt on some parts of Israel's accounts.

The audio analysis focused first on which direction the rocket could have actually been fired from, and was carried out by Earshot, which describes itself as an organization that produces audio investigations for human rights advocacy.

Lawrence Abu Hamdan, director of the investigations at Earshot, explained the Doppler sound analysis in the Channel 4 video, saying "it's the compression of sound waves as a moving object is accelerating towards you and that object is emitting sound and then as it's moving away that frequency decreases, that pitch decreases."

According to their Doppler sound mapping analysis, the rocket that hit the hospital did not come from within southwestern Gaza as the Israelis claim, but from a variety of possible firing points east of the hospital.

And while this technique can provide important clues about the events surrounding the blast, it can also have certain limitations, especially if basic evidence is limited or the sound is not clean.

"It's not a precise science," said Tilman Wagner, an expert on open-source investigations and an innovation manager at DW. "In this case we're talking about basically a 360-degree field where the rocket could be coming from. That's why they can only limit it so far, but they can't give an exact location of where the rocket was flying past."

The second piece of evidence that was analyzed is a recording published by the IDF. They claim it refers to two Hamas fighters discussing how a missile fired by the Islamic Jihad malfunctioned and landed in the al-Ahli hospital. 

However, the forensic sound analysis said "this recording is made up of two separate channels [and] demonstrates that these two voices have been recorded independently. These have then been edited together in a digital audio workstation."

Therefore, they said, "the level of manipulation required to edit these two voices together disqualifies it as a source of credible evidence."

In addition to the Earshot analysis, Arabic-speaking experts at Channel 4 had already raised questions about the "tone and language" of the recording. 

DW's Wagner explained that the audio analysis is "not 100% precise, as they stated as well, but at least it sheds doubt on whether this is a proper recording or whether it's been manipulated by cutting voices together to have a conversation."

Analysis of impact crater 

The crater left behind by the explosion is one of the most critical pieces of evidence, as it can be used to determine where the rocket was fired from and what type of rocket might have been used.

The team at investigative journalism group Bellingcat has identified what it said appeared to be the impact crater and in its analysis cites a post by Marc Garlasco, a former UN war crimes investigator and military adviser at the Dutch organization PAX Protection of Civilians. 

According to Garlasco, the "widespread surface damage and total lack of cratering" was "inconsistent with an airstrike."

His post on X, formerly Twitter, explains that "even the smallest JDAM leaves a 3m crater." JDAM's stands for Joint Direct Attack Munition, a guidance kit that converts unguided bombs into precision-guided munitions with the help of a GPS receiver. As this system was developed by the US Air Force and US Navy, it would have been used by the Israeli army in this case. 

This analysis backs up Israel's insistence that none of its munitions caused the blast.

"Whatever hit the hospital in Gaza it wasn't an airstrike," Garlasco concluded.

In a separate post he points to the fact that Hamas has not produced any remnants of the alleged Israeli missile: "In 20 years of investigating war crimes this is the first time I haven't seen any weapon remnants. And I've worked three wars in Gaza."

Other analysts like Nathan Ruser of the Australian Strategic Policy Institute, which is partially funded by Australia's Department of Defence, have also said on X that the images of the site did not suggest a massive blast or explosion as would have been caused by an airstrike.

Channel 4's visual analysis also looked at images of the crater outside the Al-Ahli Baptist Hospital. The crater left behind by the explosion is one of the most critical pieces of evidence, as it can be used to determine where the rocket was fired from and what type of rocket might have been used.

Channel 4 concluded in its report that the image analysis of the crater done by Forensic Architecture, a research agency based at the University of London, matched the audio analysis of the missile track. According to them, the rocket that was used had been fired from the northeast and not from the southwest of Gaza, as the IDF says. However, analysts stressed that it was a preliminary investigation and that a full investigation was needed, which is unlikely at the moment. 

Latest investigations question IDF version of events

The New York Times has found inconsistencies in one video which Israeli officials described as evidence to make their case. 

According to the newspaper, the video "is an unrelated aspect of the fighting that unfolded over the Israeli-Gaza border that night." 

The analysis said the video clip, which was recorded by an Al Jazeera television camera streaming live, actually shows something else.

"The missile seen in the video is most likely not what caused the explosion at the hospital. It actually detonated in the sky roughly two miles away," wrote The New York Times.

In the report of its investigation, The New York Times concluded that the missile in the video was never near the hospital. It also added that the rocket was launched from Israel, not Gaza, and appears to have exploded above the Israeli-Gaza border, at least 2 miles (about 3.2 kilometers) away from the hospital. 

"The darkness, a lack of footage before the blast, and timeliness" was one of the main challenges of the verification work says Riley Mellen, video journalist in the Visual Investigations team of The New York Times.

"Since the explosion happened in the dark, it was incredibly difficult to not only geolocate significant events and places [...] but also to simply see what was happening! If it was daylight, this would have been a totally different story. The few [videos] that did come out were nonetheless crucial in determining a timeline, a chain of events, and cause-and-effect."

The New York Times, however, does state that "the contention by Israeli and American intelligence agencies that a failed Palestinian rocket launch is to blame remains plausible."

The paper also cites US authorities as having told them they had a high level of confidence that an Israeli rocket was not the source of the explosion.

Edited by: Martin Kuebler

This article was updated on October 28 with additional information.