Few events - not even the execution of Osama bin Laden - have caused me greater pleasure in recent weeks than news of the death of the Italian so-called "peace activist" Vittorio Arrigoni.

On Thursday 14 April Arrigoni was murdered in Gaza by members of Jama'at al-Tawhid wal-Jihad (JTJ), who had him strangled and then dumped his body in a deserted Gaza apartment. This same group had previously had him kidnapped in order - apparently - to compel the Hamas government of Gaza to release the group's leader, Sheikh Abu al-Walid al-Maqdisi.

Hamas was naturally having none of this, and launched a search for Arrigoni, whose murder may have been ordered to prevent discovery of the kidnappers, though it is just as likely that the deed was carried out merely as a routine (so to speak) quasi-judicial punishment for the crime of being a foreigner (i.e. a non-Muslim) in a Muslim land.

JTJ is an al-Qaida affiliate. Its precise history is necessarily obscure, but it seems to have originated in Iraq, where it has resorted to any means (including the use of chlorine gas) in the pursuit of its goal of turning Iraq, post-Saddam, into an Islamic state.

In Gaza it has sought to establish itself as an alternative government to that of Hamas. Its religious leader, al-Maqdisi, by birth an Egyptian, is credited amongst many other things with having orchestrated the murder of western tourists in Sinai in 2006. He is certainly the author of a fatwa enjoining the kidnapping and killing of tourists in countries ruled by what he and his followers would regard as "apostate" Muslim governments. At the beginning of March this year he was detained by Hamas, perhaps at the request of the Egyptian authorities.

The death of a Jew-hater must be a cause for celebration

But my concern is less with Abu al-Walid al-Maqdisi than with Vittorio Arrigoni, whose killing was immediately pounced upon by the western media as an affront to the civilised world. Even Hamas felt impelled to associate itself with these encomia.

The Italian was described as a "peace activist." But the truth is very different. Vittorio Arrigoni, a disciple of the International Solidarity Movement, had travelled to Gaza to assist in the breaking of the Israeli naval blockade. As a supporter of Hamas he was a consummate Jew-hater. His Facebook page contained not merely the customary insults aimed at Israel but explicit anti-Jewish imagery, which may have reflected in part his Catholic upbringing: one image, for example, shows Jesus under arrest by Israeli soldiers.

The death of a consummate Jew-hater must always be a cause for celebration. In this case, however, the benefit is compounded by the dissensions that it has sown within the wider Israel-hating and Jew-hating fraternities.

Some members of these fraternities, ignoring or (in one case) making a virtue of the complete absence of evidence, have actually accused Mossad of his murder, alleging (in the wake of the Goldstone Retraction) that Arrigoni alone knew "the truth" of Operation Cast Lead. The Zionists, according to this argument, having forced Richard Goldstone to withdraw his contemptible allegation that during Cast Lead Israeli troops deliberately targeted civilians, needed to silence Arrigoni lest "the truth" be told.

But what particularly caught my eye was the emotional plea for Arrigoni's life posted on YouTube by Ken O'Keefe, the former US marine who has taken it upon himself to espouse the cause of Hamas and with whom I appeared on Press TV last year.

Arrigoni is not the first ISM activist to be murdered by Palestinian Arabs. In September 2007 Akram Ibrahim Abu Sba' was killed in Jenin by members of Islamic Jihad. But in his video plea O'Keefe ignored this precedent, and engaged instead a typical rant not only against the Jewish state but against its Christian supporters. Whoever had kidnapped Arrigoni, he argued, had branded themselves as collaborators of Israel and of its Zionist enterprise. And he repeated the charge of collaboration in a further video made after the discovery of Arrigoni's body.

The idea that JTJ - or indeed any fundamentalist Islamic group of the Salafist variety - would collaborate with Israel is too fanciful to merit attention. But in putting forward this argument O'Keefe has revealed himself as completely detached from reality.

During our Press TV discussion O'Keefe challenged me to a public debate. Naturally I accepted, and we subsequently fixed the date – 28 April 2011. This date has come and gone. But if we manage to reschedule the event I'll let you know.