A Palestinian citizen of Israel began the final year of his minimum 40-year jail sentence on Tuesday, Anadolu Agency reported.
Maher Younes, 64, was detained on 18 January 1983 in Israel's Haifa district, accused of murdering an Israeli army soldier, membership of the Fatah political movement, and unlawful possession of weapons, according to the Palestinian Prisoners' Club (PPC), which supports Palestinians incarcerated in Israel.
As an Israeli national, Younes was originally set to be executed for "treason". He was instead given a life sentence a few weeks later.
His sentence was amended again in 2012, to a minimum term of 40 years.
Younes was meant to have been released in 2013 as part of a deal between Israel and the Palestinians, The New Arab's affiliate Arab 48 reported.
However, Israel ended up backing out of the deal, the news site said.
Younes is the second longest-imprisoned Palestinian in Israeli detention, Anadolu reported. He is second only to his cousin, Karim Younes, who was also arrested and charged in connection with the Israeli soldier's murder.
Karim Younes is slightly further through his fortieth year in detention. His sentence had also been amended from the death penalty to a 40-year minimum term.
Maher Younes was tried in a military court. Israel has been widely criticised for trying Palestinian civilians in these courts – a practice that continues today in the occupied West Bank.
There were about 4,600 Palestinian prisoners in Israel as of 5 January, Palestinian prisoners' rights group Addameer said. Hundreds of prisoners are held without trial in "administrative detention".