Rhino: Agencies – Information is still unfolding about the nature of the killing of Hamas political bureau chief Ismail Haniyeh in Tehran on Wednesday, after talking about a missile targeting his residence, seven officials revealed that an explosive device secretly smuggled into the guesthouse in Tehran where he was staying was what led to his death.

The bomb was hidden about two months ago in the guesthouse, according to five Middle East officials. The guesthouse is run and protected by the Revolutionary Guards and is part of a large complex, known as Nashat, in an upscale neighborhood north of Tehran.

The bomb was detonated remotely, once it was confirmed that he was inside his room at the guesthouse, the five officials said. The blast also killed a bodyguard, according to the New York Times.

The blast shook the building, shattered some windows and caused a partial collapse of an exterior wall, according to the Iranian officials, members of the Revolutionary Guards who were briefed on the incident.

This damage was also evident in a photo of the building, which was shared with the New York Times.

Haniyeh, who headed Hamas’ political bureau in Qatar, stayed at the guesthouse several times during his visit to Tehran, according to the officials, who spoke on condition of anonymity to share sensitive details about the assassination.

Israel has not recognized:

Iranian and Hamas officials said on Wednesday that Israel was responsible for the assassination, an assessment also made by a number of US officials, who spoke on condition of anonymity.

The assassination threatened to unleash another wave of violence in the Middle East and derail ongoing negotiations to end the war in Gaza. Haniyeh was a top negotiator in the ceasefire talks.

While Israel has not publicly acknowledged responsibility for the killing, Israeli intelligence officials briefed the United States and other Western governments on details of the operation in the immediate aftermath, according to the five Middle East officials.

Secretary of State Antony J. Blinken said on Wednesday that the United States had no prior knowledge of the assassination plot.

The missile theory:

In the hours following the killing, speculation immediately centered on the possibility that Israel had killed Haniyeh with a missile strike, possibly launched from a drone or carried out by a fighter jet, similar to the way Israel fired a missile at a military base in Isfahan in April.

This missile theory also raised questions about how Israel managed to evade Iran’s air defence systems once again to carry out such a brazen air strike in the capital.

As it turned out, the assassins were able to exploit a different kind of loophole in Iran’s defences: a loophole in the security of a supposedly tightly guarded compound that allowed a bomb to be planted and hidden for several weeks before it was finally detonated.

An intelligence failure:

Three Iranian officials noted that such a breach would have been a catastrophic intelligence and security failure for Iran and a huge embarrassment for the IRGC, which uses the compound for secret retreats and meetings, and to house high-profile guests such as Haniyeh.

It remained unclear how the bomb was hidden in the guesthouse. Officials in the Middle East said the assassination took months to plan and required extensive surveillance of the compound. The two Iranian officials who described the nature of the assassination said they did not know how or when the explosives were planted in the room.

Israel decided to carry out the assassination outside of Qatar, where Haniyeh and other senior members of Hamas’ political leadership live.

Photos showed that the deadly explosion, which occurred early Wednesday morning, shattered windows and collapsed part of the compound’s wall. The damage did not appear to extend beyond the building itself, as a missile would likely have done.

He died instantly:

At about 2 a.m. local time, the device exploded, according to Middle Eastern officials, including Iranians.

Panicked building staff rushed to find the source of the massive noise, which led them to the room where Haniyeh was staying with a bodyguard, the officials said.

The compound was equipped with a medical team that rushed to the room immediately after the explosion. The team declared Haniyeh dead on the spot. The team tried to revive the bodyguard, but he also died.

Two Iranian officials said Palestinian Jihad leader Ziyad al-Nakhaleh was staying in the room next door. His room was not badly damaged, indicating careful planning in targeting Haniyeh.

They woke Khamenei at midnight:

According to the five Middle East officials, Khalil al-Haya, Hamas’ deputy leader in the Gaza Strip, who was also in Tehran, arrived at the scene and saw the body of his colleague.

Among those immediately notified, the three Iranian officials said, was General Ismail Qaani, commander-in-chief of the Quds Force, the IRGC’s external arm, which works closely with Iran’s allies in the region, including Hamas and Hezbollah.

He informed Iran’s supreme leader, Ali Khamenei, in the middle of the night and woke him up, officials said.

Four hours after the explosion, the IRGC issued a statement that Haniyeh had been killed. By 7 a.m., Khamenei summoned members of Iran’s Supreme National Security Council to his compound for an emergency meeting, at which he ordered a strike on Israel in response, according to the three Iranian officials.

Tehran had already seen tight security for the inauguration of Iran’s new president Massoud Bazeshkian, with top government officials, military commanders and dignitaries from 86 countries gathered at the parliament in central Tehran for the ceremony.

Haniyeh appeared jubilant and triumphant on Tuesday during the swearing-in, hugging the new president after he delivered his inaugural speech, and the two men raised their hands together, signaling the sign of victory.