'Hold me' Vic shooting victim asked friend

Andrew Toumayan was shot the instant he set foot outside the Ringwood property he'd broken into, intending to steal drugs.

His friend Francesco Vigneto, just five metres behind, heard a single gunshot and Mr Toumayan let out a noise.

He jumped a fence and ran onto the street to catch up with Mr Toumayan who, despite being hit, was still fleeing the scene.

Mr Vigneto picked up Mr Toumayan the first time he collapsed and they continued running, around a corner and down another street until the dying man collapsed again in a driveway.

He told Mr Vigneto he couldn't breathe and asked him to "hold me".

Mr Vigneto sat on the ground behind Mr Toumayan, brought him up to his chest and held him.

"I could see my mate lying there on the ground, blood coming out of his mouth," he told Victoria's Supreme Court on Tuesday.

"I checked for a pulse. I found no pulse, tried to do mouth to mouth and pump his chest. It didn't work."

The fatal shot was allegedly fired by 33-year-old Albert Biba, an accused cannabis cultivator who was linked to the Ringwood house.

He's charged with Mr Toumayan's murder and cultivating drugs inside the home. Police found 74kg of plants, nearly three times what is considered a commercial quantity.

Mr Toumayan and Mr Vigneto's snoop around the house - which lasted just 10 minutes after realising the plants weren't ready yet - had triggered a silent alarm.

Biba was allegedly contacted by an associate about the alarm and a short time later his rented car was captured on CCTV being driven from his Box Hill apartment to Ringwood.

His barrister Robert Richter QC, who assured jurors in his opening remarks that his sniffs were only hayfever, said there was no dispute that Biba was involved with the crop house.

His DNA was found on a TV remote on the mantle piece, as well as on forks in the kitchen sink.

But Mr Richter said the case was circumstantial and even if jurors found Biba had cultivated the drugs, they must consider the murder case separately.

He said it's possible two people had travelled in the 4WD to the property and only one of them fired the fatal shot.

Jurors had to be certain beyond reasonable doubt that if there were two people in the car, it was Biba who fired the gun.

They must also be certain the shooter intended to kill Mr Toumayan or at least cause him really serious injury.

Circumstances in dispute include whether the shot was fired accidentally or in a panic, whether there was an intent to frighten or injure because of a perceived need for self-defence, or whether the projectile was somehow deflected.

The trial is continuing.