Australian police say the terror suspect shot and killed this week after attacking two officers may have not been working alone, as investigators initially thought.
Eighteen-year-old Abdul Numan Haider was killed Tuesday after stabbing the officers outside a police station in Melbourne, where he had arrived for questioning.
There has been speculation Haider was linked to or inspired by the Islamic State extremist group, which a day earlier encouraged its adherents to kill Australians.
Investigators initially said they believed the teenager was acting alone, but Victoria state police chief Ken Ray told the Australian Broadcasting Corporation new information suggests Haider was "talking to other people around the time that he came to the police station."
Ray added that authorities are investigating whether someone dropped Haider off at the police station and whether they were waiting to pick him up after the attack.
Police on Wednesday referred to Haider as a "known terror suspect." His passport was canceled last week on security grounds amid concerns he was recently seen in a shopping mall with an Islamic State flag.
In a speech Wednesday at the United Nations, Australian Prime Minister Tony Abbott appeared to blame the Islamic State for Haider's actions, slamming the group as a "death cult."
The extremist group this week urged the indiscriminate killing of citizens in Australia, Canada, France and others that have joined the global coalition against the jihadists.
Australia has agreed to send at least 600 soldiers and 10 aircraft to help in the U.S.-led coalition against the group, which controls large parts of Syria and Iraq.
Last week, Australian police conducted a massive anti-terrorism raid, which authorities said was prompted by an Islamic State figure who ordered "demonstration" killings in Australia.
The government estimates around 60 Australians are fighting with the Islamic State group and that another 100 people are supporting the Sunni Muslim group from Australia.
The jihadist group has declared a caliphate in Iraq and Syria, where it has slaughtered ethnic and religious minorities and carried out videotaped beheadings of several foreigners.