The California company confirmed it took action to remove the page following revelations that Musa Cerantonio, an Islamic preacher from west Melbourne, was urging about 12,000 subscribers to "assassinate" US politicians.
A second US radical is believed to have deleted his Twitter account after the Guardian and the BBC reported that he had twice praised the deaths of British Muslim fighters killed in Syria on the microblogging site.
Born into an Italian family as Robert Cerantonio, the Melbourne preacher was found to be the third most "liked" person by western jihadists in Syria. The discovery came from the groundbreaking work of King's College London academics who analysed the social media habits of 190 western jihadists fighting in Syria against president Bashar al-Assad.
In one post from 16 December, Cerantonio told his followers: "If we see that Muslims are being killed by the tyrant leaders of the USA then we must first stop them with our hands [ie by force]. This means that we should stop them by fighting them, by assassinating their oppressive leaders, by weakening their offensive capabilities etc … This is not something that is beyond us at all." .
Cerantonio, who attended a Catholic primary school, says he converted to Islam in around 2002 at 17, after a visit to the Vatican left him disillusioned with Catholicism. He was particularly disgusted by Michelangelo's artwork on the roof of the Sistine Chapel – calling it idol worship.
Sources within the Australian Muslim community say Cerantonio's faith journey took him to Cairo, where he became involved with a literalist interpretation of Islam. His status as a convert also won him a spot on Islamic satellite TV stations, and a global audience.
When in Australia, Cerantonio frequented classes and events at the Ummah United centre south of Brisbane and at a now-closed bookstore in Bankstown, Sydney.
Cerantonio said he currently lived in the Philippines and Egypt and only rarely returned to his native country.
Asked if he wanted sharia, or Islamic, law to be established in Australia, he told the Guardian: "Sharia law is to be established in the lands of Islam, it is a law for Muslims, not for non-Muslims … My advice to any Muslims in Australia is to migrate to Muslim lands, especially if they wish to establish sharia and live in a land ruled by Allah's law."
It is understood Cerantonio's Facebook posts violated the site's community standards on violence. The company, which says it works with law enforcement in the event of an urgent threat, added that the networking site was a place where beliefs, however abhorrent, could be shared.
The second preacher identified in the King's College report, Ahmad Musa Jibril – a Michigan convicted fraudster turned spiritual adviser – was revealed to be the most popular on Facebook with European and North American jihadists. He has more than 190,000 "likes" and on his now-defunct Twitter account Jibril was followed by 60% of foreign jihadists in Syria.
The Palestinian-American preacher spent a portion of his childhood in Saudi Arabia, where his father was a student at the Islamic University. He is understood to have completed high school, going on to get degrees in both Islamic sharia and US law.
In 2004 he was incarcerated on several fraud charges in the US federal government's Communication Management Unit in Terre Haute, Indiana – a facility sometimes referred to as Guantánamo North .
Before this, Jibril was known to run a website that government prosecutors in his fraud trial described as containing "a library of fanatically anti-American sermons".
In a document submitted to the court in 2005, US lawyers said Jibril, using his website AlSalafyoon.com, "encouraged his students to spread Islam by the sword, to wage a holy war [and] to hate and kill non-Muslims".
A poem published on the site before 2001 entitled Al-Jihad reads: "Why are you waiting go and thrust, in the lines of enemies and have them crushed. Hit them on the neck and send them to hell, if you're killed, you'll be received There well."
It continued: "Give them a knife and a bulletful [sic] of gun … Fight, fight, and Fight, it must be our aim."
After his release from prison in 2012, Jibril sent a message of condolence last December via a series of direct messages to a member of the family of a well-known dead British jihadist, Ifthekar Jaman.
Uploaded to the family member's public timeline, the messages read: "I didn't know him [Ifthekar] but when I read of him today it made me weep, may Allah be with you and may Allah grant him ferdous [the highest level of paradise]!
"Give my salam, love and respect to all the family. If I was there it would be a great honor to visit you all."
Twitter was not available for comment.
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