This is the moment an armed robber was caught on CCTV flicking a cigarette butt into a garden seconds before carrying out a violent raid - providing police with a perfect DNA match. Mark O'Brien dropped the roll-up in a garden before launching a violent shop raid, hitting a staff member on the head with a fake handgun and ripping a £1,000 gold chain from his neck. The 26-year-old escaped but left the key piece of evidence  - which helped convict him of robbery and has seen him jailed for four years and eight months. Mark O'Brien was caught after CCTV showed him flick a cigarette butt seconds before  a violent shop raid, where he hit  a staff member on the head with a fake handgun and ripped a £1,000 gold chain from his neck . Caught: Armed robber Mark O'Brien (pictured left) was spotted on CCTV flicking this cigarette into a garden. It was this roll-up (right) lying perfectly preserved in a neighbour's garden which led him to be caught . O'Brien pointed a fake handgun at the shopkeeper during the raid in December at the Ganners Convenience Store in Leeds, West Yorkshire, Leeds Crown Court heard. He took £500 from the till and hit the shopkeeper over the head with his weapon before ripping the chain from the victim's neck. An accomplice, who has not yet been caught, was armed with a knife and made threats at the shopkeeper before the pair left. When police investigated, however, they found CCTV which showed O'Brien crossing the street and disposing of something in a garden - which turned out to be his incriminating cigarette butt. They ran a check on the Police National Computer and it brought up a match for O'Brien, who has previous convictions for robbery and violent offences. O'Brien was arrested and pleaded guilty to robbery and possession of an imitation firearm. Judge Guy Kearl QC told him: 'You are an experienced criminal and you have an extensive record of convictions. O'Brien is pictured flicking the cigarette into a garden - he has now been jailed for almost five years . 'This was a planned attack. It was persistent. Weapons were available and weapons were used to the extent of using part of the gun to cause injury.' Detective Inspector Mark Swift, of Leeds District CID, said: 'O'Brien left the crucial piece of evidence that linked him to the crime when he discarded a cigarette butt near to the scene. 'CCTV was recovered that showed the two masked suspects loitering outside the shop before the robbery. 'The one we now know to be O'Brien is seen crossing the street and flicking the cigarette butt into the garden of a nearby house, presumably so as not to leave it at the scene. 'This caught the attention of investigating officers who then recovered the cigarette butt from the garden for forensic analysis which found O'Brien's DNA on it. 'This was an excellent piece of detective work that has seen a prolific offender taken off the streets after he put the victim through a frightening ordeal. 'We hope the victim and his family are able to take some comfort from seeing him brought to justice.'
Mark O'Brien pointed fake gun at victim during £500 cash raid in Leeds .
He ripped £1,000 gold chain from shopkeeper's neck and hit him on head .
CCTV revealed he had thrown something into garden across the street .
Police investigated and found a cigarette butt with his DNA on it .
O'Brien jailed for 4 years and 8 months after he admitted robbery .
This is the moment an armed robber was caught on CCTV flicking a cigarette butt into a garden seconds before carrying out a violent raid - providing police with a perfect DNA match. Mark O'Brien dropped the roll-up in a garden before launching a violent shop raid, hitting a staff member on the head with a fake handgun and ripping a £1,000 gold chain from his neck. The 26-year-old escaped but left the key piece of evidence  - which helped convict him of robbery and has seen him jailed for four years and eight months. Mark O'Brien was caught after CCTV showed him flick a cigarette butt seconds before  a violent shop raid, where he hit  a staff member on the head with a fake handgun and ripped a £1,000 gold chain from his neck . Caught: Armed robber Mark O'Brien (pictured left) was spotted on CCTV flicking this cigarette into a garden. It was this roll-up (right) lying perfectly preserved in a neighbour's garden which led him to be caught . O'Brien pointed a fake handgun at the shopkeeper during the raid in December at the Ganners Convenience Store in Leeds, West Yorkshire, Leeds Crown Court heard. He took £500 from the till and hit the shopkeeper over the head with his weapon before ripping the chain from the victim's neck. An accomplice, who has not yet been caught, was armed with a knife and made threats at the shopkeeper before the pair left. When police investigated, however, they found CCTV which showed O'Brien crossing the street and disposing of something in a garden - which turned out to be his incriminating cigarette butt. They ran a check on the Police National Computer and it brought up a match for O'Brien, who has previous convictions for robbery and violent offences. O'Brien was arrested and pleaded guilty to robbery and possession of an imitation firearm. Judge Guy Kearl QC told him: 'You are an experienced criminal and you have an extensive record of convictions. O'Brien is pictured flicking the cigarette into a garden - he has now been jailed for almost five years . 'This was a planned attack. It was persistent. Weapons were available and weapons were used to the extent of using part of the gun to cause injury.' Detective Inspector Mark Swift, of Leeds District CID, said: 'O'Brien left the crucial piece of evidence that linked him to the crime when he discarded a cigarette butt near to the scene. 'CCTV was recovered that showed the two masked suspects loitering outside the shop before the robbery. 'The one we now know to be O'Brien is seen crossing the street and flicking the cigarette butt into the garden of a nearby house, presumably so as not to leave it at the scene. 'This caught the attention of investigating officers who then recovered the cigarette butt from the garden for forensic analysis which found O'Brien's DNA on it. 'This was an excellent piece of detective work that has seen a prolific offender taken off the streets after he put the victim through a frightening ordeal. 'We hope the victim and his family are able to take some comfort from seeing him brought to justice.'
CCTV flicking a cigarette butt into a garden and has seen him jailed for four years and eight months. Mark O'Brien was caught after CCTV showed on the head with a fake handgun and ripped a £1,000 gold chain from his neck . Caught: Armed to be caught . O'Brien pointed a fake handgun at the shopkeeper during the raid in December at the from the till and hit the shopkeeper over the is seen crossing the street and flicking the O'Brien's DNA on it. 'This was an excellent piece