An Italian peace activist has become the second non-Palestinian to be murdered in just over a week in the occupied territories.
Vittorio Arrigoni was murdered by the Tawheed and Jihad group, one of several extremist Islamic groups that operate in the Gaza Strip in opposition to the Hamas government. The group abducted Arrigoni in an attempt to force Hamas to release its leader, who was arrested last month.
Arrigoni's death comes just over a week after a gunman shot dead Juliano Mer-Khamis, an Israeli actor who ran a theatre in the West Bank city of Jenin. It is not clear why Mer-Khamis was shot but his views about freedom of expression had generated some opposition in Jenin.
Arrigoni, known as Vik, lived in an apartment that he rented separately from his fellow volunteers for the International Solidarity Movement (ISM). The first anyone knew of his abduction was when video was posted on YouTube in which Arrigoni appeared blindfolded with a bruised face.
The accompanying Arabic text said: "The Italian hostage entered our land only to spread corruption." It described Italy as "the infidel state".
On the day he was abducted, Arrigoni had written three posts on his Guerilla Radio blog: a report on the deaths of four men in the south of Gaza in a collapsed tunnel and comments on Silvio Berlusconi, the Italian prime minister, and Hosni Mubarak, the former Egyptian president.
He was last seen at a Gaza City gym on Wednesday and from there he ordered food by telephone but never arrived at the restaurant to pick it up.
Nathan Stuckey, a volunteer from the United States, said Arrigoni spent most of his time working as a journalist but was also involved in promoting the rights of Gazan fishermen to fish freely without hindrance from the Israeli navy.
"At the moment, he was particularly focused on the launch of our new boat, which we will use to monitor the navy's violations of the rights of the fishermen. He often said that he now felt more at home in Gaza than in Italy and he was strongly committed to the Palestinian cause," Stuckey said.
Foreigners and outsiders are normally warmly welcomed in Palestinian communities, who regard them as allies against Israel. Previously the greatest risk for foreigners was seen to be from the Israeli army. Rachel Corrie from the US and Tom Hurndall from London were killed by Israeli forces in Gaza in 2003 and 2004 while volunteering for the ISM.
Hamas is widely perceived around the world as a radical Islamic group but since it participated in elections and took control in Gaza, it has become more mainstream. Small groups inspired by al-Qaida or other Islamist groups have emerged and find willing supporters among young people, of whom more than 70% are unemployed.
The Army of Islam emerged from the Popular Resistance Committee and initially carried out operations with Hamas such as the kidnapping of Gilad Shalit in 2006. When relations between Hamas and the Army of Islam broke down the Army began kidnapping foreigners, including two people from Fox TV in 2006 and the BBC's Alan Johnston in 2007. Johnston was held for four months before he was released unharmed.
Since then Hamas has worked hard to ensure the security of foreigners in Gaza and suppress groups that challenge its authority. Many of the leaders of the Army of Islam, who were mostly from the Dogmush family, were killed or arrested by Hamas and some were also killed in Israeli air attacks.
In 2009, Sheikh Abdel Latif Moussa proclaimed an Islamic emirate from his mosque in Rafah. Hamas forces surrounded the mosque and killed the sheikh and 23 of his followers. The group had previously launched an unsuccessful attack on Israeli border positions.
Another group called the Sword of Truth has bombed internet cafes and beauty parlours and was believed to have been behind the murder of a Christian bookseller in 2007.
Tawheed and Jihad, which means the oneness of God and holy war or struggle, were led in Gaza by Sheikh Abu Walid-al-Maqdas, a Jordanian Palestinian who was arrested by Hamas last month.
Arrigoni's kidnappers gave a Friday deadline for the release of the sheikh but the Italian was believed to have been killed soon after his abduction, probably because his captors feared being caught.
Ehab al-Ghassain, a spokesman for the Hamas interior ministry, told a news conference on Thursday that the arrest and questioning of one of the group had led to the discovery of where Arrigoni was being held, but when forces arrived at the scene he was dead.
"The forces moved quickly and wisely to the place but found that the abducted man was killed hours earlier in an ugly manner, according to the pathologist," Ghassain said.