A man accused of gunning down a gangland figure in a supermarket car park was acquitted today after the case against him collapsed.

Ross Monaghan, 30, was on trial accused of repeatedly shooting and murdering Kevin "Gerbil" Carroll outside Asda in Robroyston, Glasgow, on January 13 2010.

At the High Court in Glasgow today, the trial judge ruled there was no case to answer due to insufficient evidence.

Outside court, Mr Monaghan told reporters: "I've always said this was nothing to do with me. I'm just so glad it's over and now I can put it behind me."

During the 18-day trial, jurors heard that two masked men drew up to the Audi car Mr Carroll was in and shot him dead while he was trapped in the back seat, before speeding away.

Mr Carroll was shot in the head, chest, arm, hand, groin, back and abdomen, with one of the bullets leaving his brain exposed.

One witness recalled seeing fragments of skull on the back seat of the car, while another described the shooting as being like "another Dunblane".

A bullet was found lodged in the car's manual, suggesting that Mr Carroll had tried to use it to shield himself from the shower of bullets.

The murder weapons - a pistol and a revolver - were found by six council gardeners 13 days later, dumped behind Coatbridge Library in Academy Street, North Lanarkshire. The gardeners went on to handle and "pass them around" while wearing wet gloves.

DNA matching Mr Monaghan's was found on the pistol but forensics experts were unable to tell the trial how it got there as it was such a tiny amount.

The jury was told the size of the sample was "one billionth of a gram", or 0.1 of a nanogram. Humans shed on average 400,000 cells, each holding about one nanogram of DNA, every day, the court heard.

Jurors also heard there was DNA of "at least three other people" on the same gun.

Lord Brailsford said it was "impossible" to say whether Mr Monaghan's DNA had arrived there as a result of primary, secondary or tertiary means, and that a "more remote" transfer could not be excluded.

The Crown had argued that a second "covert" phone allegedly used by Mr Monaghan to contact another man implicated in the murder, who cannot be named for legal reasons, was "suspicious and sinister".

However, Lord Brailsford said he considered it "fatal to their conspiracy theory" that the apparent "covert" phone was last used 10 minutes before the meeting between Mr Carroll and Steven Glen was arranged.

The court heard that Mr Glen had set up the meeting after being "threatened" by Mr Carroll, who told him he would be selling drugs for him from then on.

Lord Brailsford also said no evidence had been led about a third phone which the Crown had argued was involved in the murder, despite police compiling a list of 99 suspects after Mr Carroll's death. Mr Monaghan was not on the police's suspect list.

Defence QC Derek Ogg made a legal submission to the court on Tuesday and Wednesday, arguing that the evidence was insufficient in law to convict Mr Monaghan.

Also on Tuesday, advocate depute Iain McSporran, deleted five of the seven charges against Mr Monaghan, which related to resetting the stolen vehicle used during the shooting and possessing guns and ammunition.

Lord Brailsford told the court: "I am unable to accept that the Crown's theory has any evidential basis.

"I uphold the no-case-to-answer speech and acquit the accused of charges two and seven (of murder and attempting to defeat the ends of justice)."