Convicted child killer Robert Black has been found guilty of murdering Jennifer Cardy in Ballinderry, County Antrim, 30 years ago. The nine-year-old was abducted from the roadside near her home on 12 August 1981. It emerged during the trial that the 64-year-old was a predatory paedophile with a history of abusing young girls. Black, originally from Grangemouth in Scotland, is serving life in prison for the murders of three children. The jury in the trial at Armagh Crown Court was sent out to consider its verdict on Wednesday morning. On Thursday, Judge Mr Justice Ronald Weatherup said he did not want an outburst when the verdict was announced. When it was finally delivered, there was an audible sigh from the public gallery. Black showed no emotion. Judge Weatherup told Black: \"You have been convicted by a jury of murder. There is only one sentence that will be imposed by law. \"That\'s the sentence of life imprisonment. Accordingly, I sentence you to life imprisonment.\" He then turned to the guards and said: \"Take him down please.\" As Black was led away, Jennifer\'s mother Pat burst into tears and a member of the jury also began to cry. After Robert Black\'s conviction for a fourth murder, attention will now focus on other cases. The suspicion remains that the full horror of his past has yet to be uncovered. As a UK-wide delivery driver in the 1980s, he used his job to strike in England, Scotland and Northern Ireland. Like most serial killers, the main reason he was eventually caught was because he kept on trying to kill. Police say he is one of the most dangerous men in British criminal history. Outside the court, Jennifer\'s father said the trial had been an awful experience for the family. \"For the last six weeks we have had to endure and listen to how Robert Black kidnapped, sexually abused and murdered our daughter,\" he said. \"It has been absolutely horrendous. We heard things that, in all honesty, were not even in our imagination. \"We were confronted with the awfulness of her last few hours and what she had to suffer and it has been truly awful.\" However, he said while Black had taken his daughter\'s life, he had not destroyed the family and they left the court relieved that it was all over. Detective Superintendent Raymond Murray, who led the police investigation into Jennifer\'s death for nine years, said his thoughts were with the Cardy family. \"None of us can imagine what they have suffered over the past 30 years or, more recently, during the past weeks of this trial when the horrific events of August 1981 were re-visited,\" he said. \"Robert Black preyed on the most vulnerable, most innocent and most cherished members of society - our children, devastating families and communities along the way. \"Today\'s conviction will ensure he remains behind bars for a long time to come.\" Huge search Jennifer Cardy with her bicycle Jennifer had left her home to cycle a short distance away to meet a friend During the course of the five-week trial, the jury heard that Jennifer had left her home to cycle a short distance away to meet a friend. Her red bicycle, which had been a birthday present two weeks earlier, was later found thrown over a hedge close to her home. After a huge search operation, her body was found at McKee\'s Dam near Hillsborough, six days after she disappeared. In August 1981, Black was working as a delivery driver for a London-based poster company. The prosecution said this role brought him to the Lisburn area on 12 August, the day Jennifer went missing. Abducted He stopped Jennifer before she reached her friend\'s house, abducted her, sexually assaulted her and killed her before dumping her body at McKee\'s Dam. He had always denied killing her. During his trial it was revealed that he had been convicted of several similar crimes. In 1982, he abducted and murdered 11-year-old Susan Maxwell from the village of Cornhill-on-Tweed, close to the border between Scotland and England. Like Jennifer, Susan was sexually assaulted and her body dumped close to a lay-by. A year later, Caroline Hogg disappeared from outside her home in the seaside resort of Portobello, just outside Edinburgh. Ten days later, the five-year-old was found dead in a ditch in Leicestershire. A third girl, 10-year-old Sarah Harper, was abducted as she walked from a corner shop near her home in Morley, Leeds. Robert Black had a history of sexually abusing and murdering children She was murdered by Black and her body discovered in the River Trent in Nottingham. Black, who is originally from Scotland, was caught after abducting a six-year-old girl in Stow in the Scottish borders in 1990, nine years after Jennifer\'s murder. He had been spotted and was caught a short time later with the girl trussed up in a sleeping bag in the back of his van. He was given a life sentence for abduction and in 1994 was convicted for the murders of Susan, Caroline and Sarah.