When Mohammed Sinwar was born in 1975 in the Khan Younis refugee camp, his brother Yahya was already 13. Their family fled a village near Ashkelon in 1948 and settled in southern Gaza. Fueled by a burning hatred for the Zionist idea, the Sinwar brothers became deeply involved in subversive activities against Israel, culminating in the horrific October 7 attack on Israeli civilians.
In 1989, when Yahya was arrested and sentenced to five life terms, Mohammed was 14. He was no longer just the brother of the brutal Yahya, who personally executed suspected collaborators with Israel, but also the brother of one of the founders of Hamas.
This movement cautiously developed a military force initially based on small, isolated terrorist cells that were difficult for the IDF and Shin Bet to penetrate. In 1991, Mohammed was arrested by the IDF for suspected terrorist activity and imprisoned in Ktzi'ot Prison but released after nine months. He grew close to field commanders who later became key figures, such as Mohammed Deif, Sa'ad Al-Arabid, and others involved in developing Hamas's military capabilities.
As the attacks became deadlier, Mohammed's confidence and status grew, aided by his "brother of Yahya" reputation, which had solidified during Yahya's time in Israeli prisons.
Mohammed was also frequently arrested by Palestinian security forces under Israeli pressure and eventually spent a total of three years in their custody. His stature increased further in April 2003 when Israel resumed its counter-terror operations, and an IDF helicopter targeted and killed Sa'ad Al-Arabid, Mohammed’s close associate.
Throughout the years, Mohammed operated alongside senior Hamas commanders and maintained connections with key figures like Hassan Salameh, who was also involved in deadly terror attacks. Mohammed's ability to operate under the radar allowed him to accumulate influence and operational experience, making him a key player in Hamas's military strategy. Despite Israeli efforts, the hunt for him remained unsuccessful.
A former security official familiar with Gaza intelligence during those years revealed that, despite the lack of media coverage, more targeted operations were carried out against Mohammed Sinwar than any other senior Hamas figure today.
"Mohammed Sinwar was not only involved during the military development of the organization, from the al-Qassam Brigades to the full military wing, but he played an active and even leading role in some parts of the process. It's no coincidence that his house was destroyed several times over the past two decades. The operations to take him out were immense but unsuccessful," explained the former official.
A leader in the Schalit kidnapping
In 2006, Mohammed once again demonstrated his loyalty, first and foremost, to his brother Yahya, who was then imprisoned in Israel, and to other security prisoners by leading the operation to kidnap soldier Gilad Schalit and later holding him captive until his brother was released in 2011.
Both senior Hamas leaders and Israeli security officials were aware that Yahya would be released in the Schalit deal largely due to Mohammed's involvement in the operation.
"The issue wasn’t Yahya being on the list of those to be released, but two points have to be considered: First, how to approve the deal without releasing Hassan Salameh, who was considered more senior than Yahya in terror activity; and second, Mohammed's refusal to sign a document with Shin Bet and the IDF committing to not return to terror activities," the former official continued. "Incidentally, the Schalit kidnapping wasn’t the only operation Mohammed carried out for his brother. In 1992, he was involved in a mission led by Mohammed Deif to kidnap and murder soldier Alon Karavani."
Attorney Eyal Borda, head of the Intelligence Division in the Israel Prison Service until 2017, told Walla this week that it was well-known Mohammed Sinwar was behind the Schalit kidnapping and was holding him, despite the involvement of other terrorist organizations.
But it's important to understand the connection between the figures. The first thing Yahya Sinwar did after his release was travel to Hassan Salameh’s mother in Gaza and promise her, "I was freed, but I will do everything to free your son."
On October 7, 2023, Yahya Sinwar took a significant step, fulfilling his words in 2011.
What is sad about the process leading up to the war is that Sinwar repeatedly made his intentions clear publicly at every opportunity, sharpening his commitment to freeing security prisoners and defeating Israel. In Israel's security and political circles, these declarations were half-mocked, half-dismissed, failing to fully grasp the determination and dedication of Hamas to its extreme ideology, which had been ingrained since the late 1980s.
The successor
Upon Sinwar's release, he began accumulating power and status, partly due to his brother Mohammed, who introduced him to key figures and processes on the ground. Over time, as more senior members of Hamas's military wing were eliminated, Mohammed's value grew.
In the summer of 2014, during Operation Protective Edge, two of his close associates, Raed al-Attar and Mahmoud Abu Shamaleh—who were considered candidates to replace Mohammed Deif—were assassinated. That same day, rumors spread about Deif's death. They had gathered in a hideout to analyze the situation, but Shin Bet uncovered the meeting, and the Israeli Air Force completed the mission. The elimination of these figures further cemented Mohammed's status.
Recently, Defense Minister Yoav Gallant visited the Southern Command and received a briefing on the situation in Gaza following the assassination of Mohammed Deif, the head of Hamas's military wing.
Shortly after, a photo was circulated showing Gallant alongside Southern Command Chief Maj. Gen. Yaron Finkelman, with a computer screen in the background displaying an image of the Sinwar brothers, Yahya and Mohammed. Security sources say that since Deif’s assassination, Mohammed Sinwar has taken the lead in the military sphere. However, it is believed that they have not officially declared him as the commander of the military wing because Yahya fears criticism that the Sinwar family is taking over the organization.
"Many don’t understand who Mohammed Sinwar really is. He is an arch-terrorist who personally murdered Palestinians during interrogations, aiming to learn how the IDF and Shin Bet operate. He didn’t hesitate to torture and kill his own people," a former security official said. "The series of horrific acts he committed helped him understand the Israeli side to the point where he tried to turn agents against Israel. He can even identify aircraft by the sounds they make. No one in Hamas understands Israel's covert operational patterns better than him. He conducted all the interrogations himself, learning everything from start to finish."
According to military sources, Mohammed Sinwar is considered even more ruthless than his brother Yahya.
"Mohammed grew up in the shadow of figures like Deif, Ayyash, Shahadeh, and Al-Arabid. He witnessed Hamas's development and gained immense experience on both the Palestinian and Israeli sides," said the sources. "You won't find a key event in Hamas's military buildup over the past 25 years in which Mohammed Sinwar wasn't involved. He served as the commander of Khan Yunis, a highly senior role, and even the commanders who followed him operated under his influence. It's important to understand that he was Deif's representative on the ground, speaking with fighters, brigade commanders, and battalion leaders when Deif couldn't or wouldn't be present, which only amplified his power. On the other hand, he was fiercely loyal to Deif, never undermining him, and everyone knew that any decision he made had Deif's backing, a benefit Mohammed greatly enjoyed."
Among his skills is not only understanding Israeli intelligence and IDF tactics—evident in the events of October 7—but aligning the interests of different organizations.
One example is how he enlisted the violent and dangerous Durmush clan, responsible for smuggling weapons and drugs from Sinai to Gaza, to carry out the kidnapping of Gilad Schalit.
Additionally, he persuaded the Sinai-based "Ansar Bait al-Maqdis" group, initially affiliated with al-Qaeda, to pledge allegiance to ISIS under his influence, thereby establishing ISIS' Sinai Province. In exchange, Sinwar provided them with weapons and training for attacks against the Egyptian army in Sinai. In return, the group promised to ensure that arms shipments to Gaza would reach their destination as planned.
This collaboration demonstrated Sinwar’s understanding of combat doctrines, training, and the leadership of focused operational activity. These capabilities position him as a natural successor to Deif, which is why Israeli assessments suggest that he is involved not only in the current war efforts but also in negotiations with Israel over the release of hostages.
"I wouldn’t be surprised if Mohammed Sinwar is playing a significant role in the negotiations with Israel, including deciding which prisoners will be released," said a former security official. "He understands far better than his brother what concessions on the ground could backfire for Hamas. It’s likely that Yahya relies heavily on Mohammed's advice. Some believe that Mohammed is more cunning and ruthless than Yahya, preferring to pull the strings from behind the scenes while his brother benefits from the status he gained during his decades in Israeli prisons. I'm sure Mohammed is advising Yahya to take a hard stance on the Philadelphi Corridor because he understands its importance as a lifeline. I also think there's no way Hamas will give up Hassan Salameh in the negotiations, as he is a close friend of Mohammed. Another crucial point is that many believe Mohammed is responsible for Yahya's constant security, a task that requires immense energy and responsibility. But reality in Gaza teaches us that everyone is replaceable, and the successor is no less ruthless or dangerous than his predecessor."
Another former senior military official who knows Hamas leadership well said this week that the history of terrorism in the region shows that within an hour of a targeted killing, there is already a successor, even if it’s not officially announced.
"Just like a year ago, many didn’t know Khalil al-Hayya, a senior Hamas leader who now serves as Yahya’s deputy, or knew of Mohammed Sinwar before his image driving a jeep in a massive tunnel near the Erez crossing was revealed in the media," the official said.
The brutal group that remains after 11 months of fighting, with some hiding in tunnels and others in apartments across Gaza, indicates that the Israeli security forces still have significant work to do in dismantling the terror infrastructure.