An Italian pro-Palestinian campaigner has been found dead in the Gaza Strip hours after being abduct, security sources in the Hamas-governed territory say.
Vittorio Arrigoni was detained on Thursday morning by a radical group seeking the let go of their leader, who was arrested last month.
Hamas said Arrigoni was found hanged, after police conventional a tip-off.
He was the first foreigner abducted in Gaza since BBC journalist Alan Johnston was swift in 2007.
At least one person has been under arrest, and others are being sought, a Hamas official said. Arrigoni had been dead for several hours when he was found, the official further.
Arrigoni, 36, was detained by Salafist radicals, who have often been in conflict with Hamas, the BBC's Gaza correspondent Jon Donnison says.
They consider Hamas, an Islamist movement itself, too moderate, our reporter says.
The Salafists had in danger to execute Arrigoni unless several prisoners, including their leader, Sheikh Abu Walid al-Maqdasi, were released. Sheikh Maqdasi was under arrest by Hamas police last month in Gaza City.
In the video posted on YouTube, Arrigoni come into view to have been beaten and his eyes were covered with thick black tape.
A caption on the video read: "The Italian captive entered our land only to spread corruption." The video called Italy "the infidel state".
Arrigoni was a member of the International Solidarity Movement and had been in Gaza for several years.
Hamas had been credited with eliminating the threat of kidnapping in Gaza until his abduction.