Leo Nicholas Eliadis, 47, and Nick Parlov, 24, faced an ACT Supreme Court trial charged with arson after surveillance footage captured a hooded person setting fire to Brierly's Cafe after midnight on March 13, 2014.

There was no identifying detail in the footage, no eyewitnesses and no forensic evidence such as fingerprints or DNA, setting off a months-long investigation while detectives narrowed down the suspects and ruled out others, including a disgruntled ex-chef and the owner of a nearby cafe.

Both Parlov and Eliadis had denied the allegations but at 5pm on Thursday, after about six hours deliberating, the jury returned its unanimous verdicts, finding both guilty.

Parlov remained in custody following the verdict. Prosecutors asked Chief Justice Helen Murrell to revoke Eliadis' bail but the judge refused the request, allowing the man to leave court on strict conditions.

During the nine day trial prosecutors sought to prove Parlov was the man in the oversized green hoodie captured on the cafe's tape of the arson, while Eliadis, if not the one who drove the arsonist to Weston, lent his car to the cause and organised payment.

It was a circumstantial case that relied on difficult and "crafty" police work over many months, prosecutor Trent Hickey said.

Police had their biggest lead in surveillance footage from a nearby garden nursery, in which a car pulls up and the hooded figure in green is seen coming and going around the time of the fire.

By analysing the lights and details of the car in the nursery footage, and then searching the internet for a matching pattern, detectives concluded the car was a 1998 - 2001 Honda CRV. Linking this footage with that from a nearby car wash, this time in colour, police deduced that the car of interest was dark green.

Eliadis appeared to be the only owner of a green Honda CRV of that vintage with links to the Weston area. The court heard his godfather was the owner of a nearby cafe. Police installed listening devices around Eliadis and began listening in on his calls.

Lead investigator detective acting Sergeant Callum Hughes spent three days on the stand, walking jurors through a police investigation that included contacting more than 80 green Honda CRV owners, listening to thousands of intercepted conversations and a late night reconstruction using Eliadis' seized car.

Defence barristers had sought to cast doubt on the police conclusions, asking jurors to question how much of the car can really be seen in the grainy black-and-white footage, whether the police conclusion it was a green Honda CRV was a sound one, and why officers hadn't contacted NSW owners.

They suggested there were innocent explanations for the conversations between Parlov and Eliadis, in which the younger man is heard asking for "paper", including that Parlov had done handyman work for Eliadis.

Chief Justice Murrell thanked the jury and acknowledged the complexity of the circumstantial case it had to consider.

She ordered pre-sentence reports for both men. The case will return to court for a sentencing hearing on August 16.