A Melbourne invalid pensioner gave about $5000 to a US citizen fighting for Islamic State in Syria, police say.
The 43-year-old man was arrested at his Hampton Park home on Tuesday, 16 months after police first raided his house and seized computers and other evidence.
Investigators allege he was providing financial support to a 33-year-old US citizen through a website.
"That citizen is alleged to have been fighting in Syria in the conflict over there," Victoria Police deputy commissioner Shane Patton told reporters.
"We are also alleging that US citizen ran a website where he promoted Islamic State and has sworn allegiance to the Islamic State."
The investigation began in November 2015 and police raided the man's home in June 2016 to seize his devices.
"We were satisfied that there was material to conduct an arrest today. There has been a lot of painstaking work that has gone into the matter," Mr Patton said.
Police allege the man transferred $5000 in 10 transactions in 2013 and 2014.
They do not know how the man, who is a disability pensioner, allegedly became a supporter of Islamic State.
"Some of the funds may well have come from his pension that he was receiving to fund the foreign fighter," Mr Patton added.