The extremist ramblings have been revealed in a series of letters he wrote to security agencies and public officials posted on his website.

Monis sent deranged missives to two Australian Prime Ministers, Barack Obama, the Queen, the Pope, various government departments and media organisations.

The heads of both ASIO and the AFP and state police ministers were also in his correspondence from the middle of 2007.

The most chilling was a public letter he sent to the families of the three executed Bali bombers praising the men as a “holy group of martyrs.”

Monis told their families: “We should celebrate when a Muslim joins the martyrs.”

Policing authorities and the Attorney-General’s department had at least 10 letters that made evident Monis’s extremist beliefs.

The self-styled cleric had also posted a series of fatwas (religious rulings) encouraging terrorist attacks.

And he wrote taunting notes to the families of Australian soldiers killed in Iraq and Afghanistan, over which he was charged and convicted.

His public letter-writing campaign has raised further questions about why authorities were not closely monitoring Monis before he stormed the Lindt cafe in Sydney this week, leading to the deaths of two hostages and the terrorising of 16 others.

Man Haron Monis sent hate letters to security agencies as well as two Australian Prime Ministers, Barack Obama, the Queen and the Pope. Source: News Limited

The Herald Sun can reveal security agencies had been aware of Monis for at least seven years.

In 2007, he wrote to the heads of ASIO and the AFP complaining that he was the victim of a “terrorist plot”.

In 2008, two separate religious organisations reported Monis to federal authorities after receiving troubling correspondence from him.

A few months later Monis asked the Attorney-General about “Imam” Osama bin Laden, describing him as a “humble man with a gentle speaking style”.

On Australia Day, 2008, he wrote an open letter in which he said: “Australia is chained by evil, let us free Australia. Lesbians and gays are the cancer on the society’s body.”

Monis lectured then prime minister John Howard that he was waging a discriminatory war against Islam.

LITANY OF FAILURE ALONG PATH TO TRAGEDY

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He later claimed that a Liberal Party supporter was planning a terrorist attack to frame Muslims.

Monis came to the attention of American authorities when he wrote to then presidential candidate Barack Obama that it was a sin to hide his Islamic beliefs.

“You must rely on Allah and avoid the satanic style of politics. If God wants you to be the President of the United States of America, you will definitely be the president, no matter you hide your religion or not,” he wrote.

He wrote that Queen Elizabeth was “more useless than a prostitute” when the monarch’s office refused to contact the Australian Government on his behalf.

Former Australian Federation of Islamic Councils president Ikebal Patel said Monis bombarded his organisation with letters in 2008.

Mr Patel told the Herald Sun he was concerned that Monis was masquerading as a cleric and was asking him to take extreme positions.

“When I found out that no one knew him and he didn’t represent anyone, I just instructed the staff not to respond to him. By then I knew that the AFP were aware of him,’’ Mr Patel said.

Senior Shiite leader Kamal Mousselmani also asked the AFP to investigate Monis.

Monis issued fatwas on a question-and-answer section of his website, encouraging suicide bombers and Muslims to take up arms in Pakistan.

“When the enemy attacks, if the suicide bombing is the only possible option to defend and save the lives of human being, it is not recommended it is wajib (obligated) to save the lives of others.”

He said he hoped that one day the only culture in Australia would be Islamic.

“We believe that replacing ‘muslimculturalism’ instead of multiculturalism will bring a better future for our beloved country,” he said.

Terrorism expert Greg Barton said the website served as an “extremist manifesto” similar to the 1500-page one of Norway’s Anders Behring Breivik after he shot 77 people.

Prof Barton said authorities had treated Monis as deranged but mostly harmless.

“He was a fruitcake and a loner and he was difficult to deal with. He was not exactly keeping a low profile, and there was always evidence of extremist beliefs. He was a dumber and louder Breivik.”

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Twitter: @jameswdowling