The security hotline in Australia received 18 calls about "self-styled cleric" just three days before the attack on a Sydney café in December, according to BBC.
Australia's Prime Minister Tony Abbott released a 90-page report conducted by officials from the federal government and the government of New South Wales. Abbott plans to address the report's findings on Monday, where he plans to talk about legal and immigration system changes.
"Plainly, the system has let us down," Abbott said, according to BBC.
The calls noted in the report did not disclose an imminent attack, but were related to "offensive Facebook posts" by gunman Man Haron Monis. The report also indicates that hostage-taker Monis was "the subject of many security investigations" before the attack.
"This monster should not have been in our community," Abbott said, according to BBC.
Abbott has proposed stricter immigration controls. Monis was an Iranian refugee who had been granted asylum in Australia and became a citizen 10 years ago, according to BBC. Monis was convicted in 2012 of sending hate mail to families of Australian soldiers who had died in Afghanistan. He had been charged with conspiring to murder his ex-wife, who was stabbed and set on fire and was out on bail for multiple sexual assaults at the time of the siege on the Lindt café.
Abbott said that although "the decisions made were reasonable at the time," according to BBC, the incident might lead to stricter visa allowances and bail controls.
