The accusations have been levelled by 26-year-old Ali Kassae, a former member of Sheik Omran's fundamentalist Ahlus Sunnah Wal Jammah association, who was married to Sheik Omran's daughter, Zaynab, until they separated in August last year.
Mr Kassae claims he has been prevented from seeing his children since the split, and has been threatened and abused by other members of Sheik Omran's group.
He also accuses Sheik Omran's organisation of inciting violent attacks on people who disagree with them.
Mr Kassae, who moved to Australia from his native Syria as a nine-year-old, blames the break-up of his seven-year marriage on the extremism of Sheik Omran and his group.
"I couldn't stand their attitude and beliefs," Mr Kassae said. "I had left that culture behind. I just wanted to live an Australian life. Then I was forced into the culture again."
Mr Kassae said he and other group members were "taught to hate" by being shown violent propaganda videos about conflicts involving Muslims in places such as Palestine. One DVD, shown to The Australian, which Mr Kassae said was distributed among members of Ahlus Sunnah Wal Jammah, declares: "You should hate them as they hate you, invade them as they invade you, fight them as they fight you. Whoever dies will be granted the mercy of God and paradise. Jews have no place in Palestine. Jews shouldn't be there. Jews should die. We should proclaim jihad until they all die, until every single one of them is dead."
A spokesman for Sheik Omran yesterday said the cleric completely rejected Mr Kassae's statements, claiming his estranged son-in-law had a "mental illness".
Sheik Omran's organisation has been under close scrutiny by ASIO for years and several of its members are known to have undergone training with the militant group Lashkar-e-Toiba in Pakistan.
In 2000, members of the group were raided by NSW and Australian Federal Police. Mr Kassae said he was visiting a fellow Ahlus Sunnah Wal Jammah member in Sydney's Wiley Park, when armed police burst in.
"There was an AK-47 loaded next to me with an 80-round magazine," Mr Kassae said. "The house was full of weapons. It was like they were preparing for war." The police seized an AK-47 assault rifle, handguns, shotguns and grenades, according to Mr Kassae.
In an affidavit filed in the Federal Magistrates Court in Melbourne in November, Zaynab Omran cited her husband's paranoia about ASIO among the reasons for their marriage break-up.
"He thought that I was in contact with ASIO or the CIA about him, and thought people were out to get him," the affidavit reads.
"He would leave pornography magazines everywhere, and told me that this was to confuse ASIO or the CIA if they ever raided the house."
Mr Kassae was a troubled street punk who had dabbled in drugs and had run-ins with the police when he was recruited into Sheik Omran's group by his brother-in-law, an Ahlus Sunnah Wal Jammah member.
Sheik Omran, who knew Mr Kassae's mother, proposed that the 17-year-old marry his daughter, Zaynab, then aged just 15.
"I was ripped out of my life and put in this life," Mr Kassae said. "I was just a kid trying to grow up. I wasn't into it for the religion.
"I was a child. I looked at them as role models."
The newlyweds went to live with Sheik Omran's family in Melbourne, where Mr Kassae worked on construction sites before setting up his own mobile phone business.
A reference from one employer described him as "always reliable, punctual and respectful".
Mr Kassae said that Sheik Omran put him in charge of "security" for his organisation, which involved looking after visiting sheiks from overseas, and helping to organise the weekend bush camps where Ahlus Sunnah Wal Jammah members would engage in paintball skirmishes, described by one participant as "jihad training".
By Mr Kassae's account, his life was totally controlled by Sheik Omran and his group. "I wasn't meant to have any friends but them, I couldn't talk to anybody but them, I couldn't do anything without their permission.
"It was like, 'You want to be part of this family - this is how it's got to be. This is who you've got to be now, and this is what you've got to do.' Basically, they wanted me to be a sheep - he's the shepherd and I'm the sheep."
Mr Kassae claimed he became increasingly disturbed by Sheik Omran's puritanical interpretation of Islam.
"I couldn't hack their understanding of Islamic teaching," he said. "Their teaching was inappropriate. It was like they were God's angels given a key to paradise. So who are we? Slaves from hell?"
Mr Kassae said the group was paranoid about anyone they suspected of talking to ASIO, including Sydney man Mamdouh Habib, who was believed by some members to be an ASIO informant. Mr Kassae has told Mr Habib's lawyer that a meeting was held in Lakemba in Sydney's southwest in 2000 where it was agreed to "do something about this guy (or) he will destroy us".
A group of Ahlus Sunnah Wal Jammah members later physically attacked Mr Habib outside the association's Haldon Street prayer room. Mr Habib was treated at Bankstown hospital for cuts and bruising to his head.
Mr Habib was arrested as a suspected terrorist in Pakistan in late 2001 and held by the US at Guantanamo Bay in Cuba until his release without charge in February 2005.
In November 2005, Mr Kassae was accused by fellow Ahlus Sunnah Wal Jammah members of being an informant, after several of the group's followers were arrested in ASIO raids in Sydney and charged with terrorism-related offences.
Ostracised within the group and with his marriage failing, Mr Kassae said he became depressed and took to drugs again. In May last year, after an amphetamines binge, he was admitted to the mental health unit of the St George hospital, in Sydney's south, where he spent a month being treated for drug-induced psychosis.
His wife cites his mental illness as the key reason for their break-up, stating in her affidavit: "There were many incidents leading up to our separation, including him disappearing for several days without explanation, and being extremely paranoid about things that were going on."
She also claims he was abusive towards her and their two children, now aged five years and 15 months.
In November, a federal magistrate granted Zaynab Omran sole parental responsibility.
A spokesman for Sheik Omran said yesterday that Mr Kassae's drug abuse and mental problems were the reason for his marriage failing.
"We appeal to Ali to seek medical help for his mental illness. We totally refute and reject the statements he has made," the spokesman said.
Mr Kassae claimed that since leaving the organisation, he had been threatened numerous times after members spread rumours that he was working for ASIO or the CIA.
In February, Mr Kassae was attacked by two men in the southwest Sydney suburb of Belmore and stabbed in the back. He was treated in the acute care facility of the Royal Prince Alfred Hospital. A NSW police report on the incident said Mr Kassae had been accused by his assailants of spying for ASIO. No one has been charged over the incident.
"Since leaving (the organisation), I've committed an even bigger crime. I've been judged - I'm a disbeliever and I should be taken apart," Mr Kassae said.
"All I wanted was a future, a wife and a family and a home. And they took that away from me."
Sally Neighbour is a senior reporter with The Australian and the ABC's Four Corners and author of In the Shadow of Swords: on the trail of terrorism from Afghanistan to Australia.
