Marwan Issa's role in the Qassam Brigades

Marwan Issa, who was considered to be one of the masterminds behind the October 7 attacks on Israel by Hamas militants, was born in a refugee camp in Gaza. Little is known about his youth, but he is said to have belonged to the Palestinian branch of the Muslim Brotherhood, the organization from which Hamas later emerged.

Issa served a five-year prison sentence in Israel during the first intifada (1987-1993). In 1997, he was arrested and jailed by the Palestinian Authority, but he was released after the second intifada began in 2000. 

He had been deputy leader of the Qassam Brigades since 2012 and a member of Hamas' political bureau.

The EU had placed him on its terror list in December 2023. Issa, who survived several targeted assassination attempts by Israel, was reportedly killed last week during an Israeli operation on a Hamas-run tunnel near the Nuseirat refugee camp in central Gaza.

'Butcher of Khan Younis:' Yehya Sinwar

Yehya Sinwar is thought to be the mastermind behind the terrorist attacks on October 7, 2023, when countless fighters of the militant group Hamas crossed the border from the Gaza Strip into Israel, killing more than 1,200 people and abducting around 240.

The most senior Hamas leader in the Gaza Strip is currently one of Israel's most wanted men. The Israeli army has vowed to eliminate him and crush the group, of which he is but one of several top commanders.

Considered charismatic and highly intelligent, as well as brutal and ruthless, Yehya Sinwar rules with an iron fist. He was born in the refugee camp of Khan Younis in the south of the Gaza Strip in 1962 and was one of the early members of Hamas when it formed in 1987.

A few years later, he was also involved in setting up its military wing, the Qassam Brigades, which has carried out suicide attacks in Israel. He was nicknamed the "Butcher of Khan Younis" after taking brutal action against Palestinians suspected of collaborating with Israel.

In 1988, an Israeli court sentenced him to four life sentences after he was convicted of killing two Israeli soldiers and murdering several Palestinians. Sinwar learned Hebrew in jail and reportedly studied the mindset of the "enemy" by reading books by famous Israeli personalities. Israeli doctors are said to have saved his life after an abscess was removed from near his brain.

In 2011, Sinwar was released after 22 years in jail, alongside more than 1,000 Palestinians, as part of a prisoner exchange deal that led to Hamas freeing the captured Israeli soldier Gilad Shalit. Sinwar returned to Gaza and became responsible for liaising between the military and political arms of Hamas. In 2017, he became the group's leader in the Gaza Strip.

Israeli Prime Minister Benjamin Netanyahu recently accused Sinwar of deliberately sacrificing Palestinian civilians in the fight against Israel. 

'Cat with 9 lives': Mohammed Deif

Mohammed Deif has led Hamas' military wing, the Qassam Brigades, since 2002. Israel has said he is responsible for several suicide attacks and the death of dozens of Israeli soldiers and civilians.

Deif is also thought to be one of those behind the extensive Hamas tunnel system in Gaza, and he too is accused of having planned and led the October 7 attacks. The Israeli army has said it wants to kill him during its ongoing military operation.

Deif has been one of Israel's most wanted men since 1995. He was temporarily imprisoned in Israel in 2000, but was able to escape during the turmoil of the second intifada, an armed Palestinian uprising that lasted from 2000 to 2005. There has hardly been a trace of him since.

He is thought to have survived seven assassination attempts, which left him seriously injured and killed several members of his family. Deif is said to have lost an eye, a foot and part of his arm. He never appears in public, and it's rumored he spends each night in a different building.

Hamas leaders in Qatar: Ismail Haniyeh and Khaled Mashaal

Since two of its most important leaders are not in Gaza but in the Gulf emirate of Qatar, it would be difficult for Israel to completely extinguish Hamas. Ismail Haniyeh, who is generally considered to be the organization's supreme leader, was also born in a Gaza refugee camp.

Haniyeh attended a United Nations school and went on to study at the Islamic University of Gaza, where he reportedly first came into contact with Palestinian independence movements. He was appointed dean of the philosophy department in 1993, and in 1997 he became the personal secretary of Hamas founder, Ahmed Yassin.

Haniyeh was appointed prime minister of the Palestinian Authority by President Mahmoud Abbas after Hamas won a majority of seats in the 2006 legislative elections. However, he was dismissed just one year later after Hamas unleashed a wave of violence to oust Abbas' Fatah party from the Gaza Strip. Haniyeh refused to step down and Hamas continued to rule the Gaza Strip, while Fatah remained responsible for the occupied West Bank.

In 2017, Haniyeh was elected head of Hamas' political bureau, succeeding Khaled Mashaal.

Mashaal was born in the West Bank in 1956 and studied physics at Kuwait University. He later lived in Syria and Jordan and was also a founding member of the Hamas political bureau, becoming its chairman in 1996. He called for terror attacks against Israel and survived a 1997 assassination attempt by Mossad, Israel's intelligence agency.

In 2012, he traveled to Gaza via Egypt to celebrate the 25th anniversary of the founding of Hamas. It was reportedly the first time he had set foot on Palestinian territories in 45 years. In 2017, he stepped down as Hamas' leader to make way for Haniyeh. He is now head of the organization's political bureau.

This article was originally written in German. It was first published on November 24, 2023 and updated on March 19, 2024 to reflect the news of the death of Marwan Issa.