Walid Daqqa, one of the longest-serving Palestinian prisoners in Israel, died of cancer on Sunday at the age of 63 after almost four decades of incarceration.

Daqqa’s case was unique. At the time of his death, he was the longest imprisoned Palestinian in Israel, with the second-longest sentence served overall, according to the Palestinian Prisoners Society.

He was also one of the few Palestinian prisoners to have been continuously incarcerated since prior to the Oslo Accords, a series of agreements between Israel and the Palestinians in the 1990s that resulted in a number of Palestinians being released from Israeli prisons. Born in the Israeli town of Baqa al-Gharbiyye in the northern “triangle” region, Daqqa was a Palestinian citizen of Israel.

A spokesperson for the Israel Prison Service on Monday confirmed Daqqa’s death and said in a statement that his death will be investigated “like any event of this nature.”

In Israel, Daqqa was seen as a terrorist after he was convicted in connection with the killing of a soldier. But to many Palestinians, he was a symbol of their struggle for liberation from Israel.

Daqqa was arrested in March 1986 and sentenced to life in prison after an Israeli court convicted him of commanding the Popular Front for the Liberation of Palestine (PFLP) militant group, which abducted and killed 19-year-old Israeli soldier Moshe Tamam in 1984. Daqqa was not convicted of carrying out the murder but of commanding the group, which he denied, Amnesty International said. Tamam’s niece Ortal said on X that her uncle was subjected to torture before being killed.

In 2012, Israel reduced his sentence to 37 years, which he completed in 2023. He was then charged by an Israeli court with smuggling mobile phones to prisoners, and was given an added sentence of two years, according to the Palestinian Commission of Detainee Affairs. He died before his scheduled release date of March 24, 2025.

The Commission and the Palestinian Prisoners Society, based in the Israeli-occupied West Bank, said in a statement that during his detention, Daqqa “faced the policies of torture, assault, deprivation and isolation, in addition to successive medical crimes.”

CNN has reached out to the Israel Prison Service for comment on the allegations.

‘Weight lifted from my chest’: niece

“The way he was murdered was so brutal and inhumane,” Orla Tamam, the niece of Moshe Tamam, told CNN on Tuesday.

Moshe had been returning from a weekend visiting his girlfriend in Tiberias when he was kidnapped at the Beit Lid Junction in Israel, according to Tamam.

“When (Daqqa) died in jail, I was very happy,” Tamam said, adding that she felt relief after she and her family had fought for years to keep Daqqa in prison rather than have his sentence reduced.

Orla Tamam, who is a medical doctor in Israel, told CNN, “to be honest, I’m a doctor, I spent my life helping people be healthy. I save life, I try to make it better for my patients. Never in my life did I think I’d be happy that someone died. But I was so happy, I felt like so much weight was lifted from my chest.”

“We fought hard to keep him in prison, and every moment of struggle paid off,” Tamam wrote on X.

Rare form of cancer

Daqqa’s health had deteriorated in prison. In 2015, he was diagnosed with neuromuscular disease after suffering from various health conditions, said Addameer, a West Bank-based prisoner support and human rights association. And in 2022, he was diagnosed with myelofibrosis, a rare form of bone marrow cancer and chronic pulmonary obstructive disease.

In 2023, Amnesty International called on Israel to release Daqqa so he could receive specialist medical care.

“The persistent lack of medical attention throughout Daqqa’s imprisonment and the prison authorities’ neglect in conducting regular check-ups had a negative impact on his health,” Addameer said, adding that prisoners have the right to receive adequate medical care under international conventions.

The group alleged that after the cancer diagnosis, “negligence” in providing urgent medical intervention meant the disease progressed and reached a “critical level three notches above the danger threshold.”

CNN cannot independently confirm the claims made by Addameer.

Amnesty International senior director Erika Guevara-Rosas said Daqqa’s death “is a cruel reminder of Israel’s systematic medical neglect and disregard for Palestinian prisoners’ rights.”

Citing Daqqa’s lawyer, she said in a statement, “For Daqqa and his family, the last six months in particular were an endless nightmare, during which he was subjected to torture or other ill-treatment, including beatings and humiliation by the Israel Prison Service.”

CNN reached out for comments regarding these specific allegations from the Israel Prison Service but they confirmed only his death and said no further comment would be provided.

During his detention, Daqqa wrote a number of books, and earned two degrees in 2010 and 2016. Amnesty described his writings as “an act of resistance against the dehumanization of Palestinian prisoners.”

After his death, a tent set up for mourners to gather on Monday in Baqa al-Gharbiyye was stormed by Israeli police, according to a statement from the Palestinian Prisoners Society and CNN video.

Israeli police said they responded to the gathering after it took place without permission, according to a statement sent to CNN, adding that five people were arrested for alleged assault against law enforcement personnel.

Amnesty International on Monday called on Israeli authorities to return Daqqa’s body to his family so they could give him a “peaceful and dignified burial and allow them to mourn his death without intimidation,” said Erika Guevara-Rosas, Amnesty International’s Senior Director for Research, Advocacy, Policy and Campaigns.

9,000-plus Palestinians in Israeli prisons

There are currently 9,400 Palestinians prisoners in Israeli jails, according to the Palestinian Prisoner’s Society.

Daqqa’s death brings the number of Palestinians that have died in Israeli custody since 1967, the start of Israel’s occupation of the Palestinian territories, to 251, according to the Palestinian Commission of Detainee Affairs.

And since Oct. 7 of last year, Daqqa is the 14th Palestinian prisoner to have died in Israeli custody, according to the Palestinian Prisoners Society.