Bourke St and Brighton siege terrorists knew each other
Terrorist Hassan Khalif Shire Ali knew the man responsible for the Brighton siege last year.
News Corp Australia can reveal Shire Ali and Yacqub Khayre socialised in the same circle of friends.
Khayre, 29, murdered receptionist Nick Hao at serviced apartments in Brighton and took a woman hostage on June 5 last year. He eventually died in a shootout with police.
During the attack, Khayre made a phone call and said: "This is for IS, this is for al-Qaeda."
The Somali-born terrorist had previously been acquitted of conspiracy to commit a terrorist attack on the Holsworthy Army Barracks in 2009.
News Corp has been told that while Khayre and Shire Ali, who was also born in Somalia, were acquainted, police had not found any direct involvement between the pair regarding any terror plots.
Counter-terrorism police investigating the Brighton siege did not come across Shire Ali, 30, as part of that probe.
"It is a small circle, they may have crossed paths, but that is not a focus (of the investigation)," a source said.
Victorian Joint Counter- Terrorism Team detectives were on Monday trying to piece together Shire Ali's recent movements to find what triggered Friday's deadly attack.
It also emerged Shire Ali became an online friend of infamous Australian terrorist Khaled Sharrouf in 2014.
Sharrouf posted a photo of his young son holding a severed head online in 2014. He was reportedly killed last year.
Shire Ali had referred to himself online as a wannabe Islamic State terrorist and had voiced his support for IS and plans to fight in the Middle East. He described himself on Facebook as a "Mujahid in sha Allah (God willing) at Islamic State of Iraq and al-Sham".
The profile appeared on Sharrouf's archived friends list, which dates back to 2014.