A former Melbourne university student has been killed while fighting for the Islamic State in Syria, according to social media reports.

A photo posted on Twitter allegedly shows the body of 23-year-old Roxburgh Park man Suhan Rahman, also known as Abu Jihad Al-Australi.

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Mr Rahman is thought to have been in the war-torn nation for seven months, but reports of his death are yet to be independently verified.

He was the subject of a police investigation in January after he made threats against a Melbourne newspaper following the Charlie Hebdo attack.

He had also threatened to “spill blood” in Australia.

An online interview with Fairfax media in January gave an insight into the psyche of Mr Rahman, a second generation Bangladeshi migrant.

The son of an electrical engineer mother and agricultural scientist father, he said the Islamic State was coming to the rescue of the Syrian people after they had been abandoned to suffer a civil war under President Bashar al-Assad.

He also defended the group’s brutal rituals such as public beheadings, and claimed one man’s terrorist was another man’s freedom fighter.

“Nelson mandella [sic] and his followers were considered terrorists also,” Mr Rahman wrote.

“But now the west kisses his arse mate.”

A woman believed to be Mr Rahman’s wife tweeted following his death: “May Allah accept my husband, Abu Jihad Al-Australi. Promised Allah and fought in the front lines until he obtained shahadah”.