A former anti-Islamic State fighter has been found not guilty of the murder of a Brisbane drug dealer, but was convicted of interfering with his corpse.

Ashley Mitchell Scott Dyball, 29, was today acquitted by a Brisbane Supreme Court jury of the 2017 killing of Brisbane cannabis dealer Samuel Thompson.

But Dyball was on Tuesday found guilty of interfering with the 22-year-old's corpse.

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Another man, Roberto Vincenzo Boscaino, was convicted of Mr Thompson's murder last year.

The Queensland jury deliberated for just five hours before reaching their verdict in Dyball's case.

Mr Thompson, 22, was stuffed in a toolbox and driven to a deserted Queensland state forest where he was buried in a shallow grave with the tomahawk used to kill him.

Boscaino was last year sentenced to life behind bars for Mr Thompson's killing.

The Courier-Mail can now reveal that five years before being acquitted of murder, Dyball travelled to the Middle East to fight death cult ISIS.

Dyball became linked to the Kurdish People's Protection Units (YPG) in 2015, who were fighting ISIS militants in Syria and Iraq, while travelling around Europe.

Using an alias "Mitchell Scott', he travelled through Amsterdam, Paris and Jordan and onto Syria, posting about his exploits on social media.

He joined Kurdish fighters just days after entering Jordan and later had a $150,000 bounty put on his head by IS.

In late 2015, Dyball was detained after entering Germany while on a break from the conflict zone in northern Syria and deported back to Australia.

He was never charged under foreign-fighters' legislation, which banned Australian citizens fighting on either side of the conflict.

Outside court, Mr Thompson's family said they were disappointed the jury did not know Dyball had travelled to Syria to fight against IS at the time they acquitted the 29-year-old.

"To say we are devastated is an understatement," Mr Thompson's father Bruce said.

"The jury can only arrive at their verdict based on the evidence it's given."

Mr Thompson's sister Courtney said the pain of losing her brother "never stops".

"Everyone loved him, nobody had a bad word to say about him. He was very generous and loving, not at all what he was made out to be," she said.

During Dyball's murder trial, the jury heard Mr Thompson died either from a blow to the face or throat, which could have been caused by the tomahawk.

The court heard after burying Mr Thompson, Dyball and Boscaino made attempts to cover their tracks.

He argued Dyball told a number of lies following Mr Thompson's death and went to a recycling centre at Nudgee to throw away items.

He told the jury Dyball assisted with dumping Thompson's distinctive Mustang in the car park at Deep Water Bend Reserve, before returning the following day to drive the car 30km over the NSW border to Pottsville.

Dyball will be sentenced tomorrow.

The maximum penalty for interfering with a corpse is five years and the court heard Dyball has already been on remand for three years.

Originally published as Former anti-Islamic State fighter not guilty of drug dealer's murder