Axel Sidaros, 25, is accused of being one of four men to sneak onto the property of former ACT Comancheros president Peter Zdravkovic on June 28, 2018, shoot at him through a glass door, and set several of his cars alight. Mr Zdravkovic lost the top of a finger in the attack.

Mr Sidaros denies any involvement and has pleaded not guilty to eight charges including attempted murder, arson, inflicting grievous bodily harm, and aggravated burglary.

In his closing remarks in the ACT Supreme Court on Monday, Mr Sidaros' defence barrister, Ian McLachlan, told the jury there was no way they could adamantly place him at the scene of the Calwell firefight and firebombing.

He said the prosecution's evidence turned up no eye witnesses who saw Mr Sidaros at the house, no conclusive forensic evidence, and CCTV footage where the assailants were unrecognisable.

Mr McLachlan said the prosecution's "lead act" or witness in the trial, serial criminal Zachary Froome, was of deplorable character, and told police a "joke" of an account to get bail and a lesser sentence.

He said if the prosecution was to have any chance proving their case against Mr Sidaros, the jury would have to accept Mr Froome as a witness - and "you wouldn't do that in a million years".

"The amount of faith you'd have in anything he says would be somewhere between nil on the one hand, and zero on the other," Mr McLachlan said.

"When you drill down on [his evidence], it's complete garbage."

Prosecutor Trent Hickey said Mr Froome couldn't have known certain details about the incident if an alleged conversation with Mr Sidaros did not take place. Mr Froome told police Mr Sidaros said he was "the one with the shotgun" in the attack, and the pair joked about his attempted murder charge.

Mr McLachlan dismissed gloves seized at Mr Sidaros' O'Malley home as a "complete red herring", and said it was no surprise police also seized a pair of tan work boots at the house given Mr Sidaros was a carpenter.

Mr Hickey previously told the court the items were similar to those in the CCTV footage.

Mr McLachlan said firearms also seized at Mr Sidaros' home, which included an Adler A-110 lever action shotgun, were bought through official channels using Mr Sidaros' firearms license. The court previously heard bullet cartridges found at the scene of the crime were "consistent" with having come from the gun.

He said Mr Sidaros' internet searches about the Comancheros and firearms in the days before the attack showed he was simply "enthused" with both.

Mr Hickey told the court Mr Sidaros was filmed at a shooting range firing the Adler the day before the attack. He had also screenshotted a Google Maps pinpoint near Mr Zdravkovic's home.

The trial continues.