Ireland's Most Shocking Crimes

Tonight we start with a crime that gripped the nation, the brutal murder of Rachel O’Reilly. Her husband Joe had what appeared to be a cast iron alibi. However, technology and dogged police work eventually solved the murder.

The investigation into the 2005 murder of a man whose dismembered body parts were discovered in Dublin's Royal Canal, eventually leading police to Charlotte and Linda Mulhall. The Scissor Sisters.

On 19 March 1996, Tom Nevin was killed with a shot from a nine pellet shotgun while counting the day's takings in Jack White's pub near Brittas Bay in County Wicklow. According to his wife, Catherine, she was woken by someone pressing her face into a pillow. She said: "It was a man shouting: 'f**king jewellery, f**king kill ya'. He had a knife in his left hand. Everything in the room was coming down around." Ir £13,000 was taken from the pub, and the Nevins' car was stolen and was found abandoned in Dublin. However, the investigators soon learned that Catherine had had numerous extra marital affairs and had tried to solicit three men to kill her husband. Nevin was convicted in 2000 of her husband's murder. The case was one of the most publicised in Irish history.

Around 3.30am, 41-year-old, Marilyn Rynn, was walking through a short cut near her home, after her work Christmas party, when she was brutally attacked, raped and murdered. Her naked body was eventually discovered on January 7 by a Garda tracker dog in bushes at Tolka Valley Park and a massive investigation began. The killing shocked the whole country. Detectives interviewed more than 2,500 people, took 1,000 statements and analysed the DNA from blood tests of 300 possible suspects. Her killer, David Lawler, had used the Internet to access information on body fluids and how long they could survive in the open without degrading, according to senior gardai. He gave gardai a blood sample, believing that his DNA would have been destroyed by the time his victim's body was discovered. However, the weather had been the coldest in 14 years and her body actually froze, so the DNA was protected. Lawler famously became the first person in the history of the State to be jailed on DNA evidence.

Peter Whelan (19) went behind a bar counter in his local pub in Cork and attempted to smash a glass ashtray on a barman's head. After being thrown out of the pub, he went home, collected a couple of knives and left his house in a murderous mood. He picked a house at random and entered via the backdoor. Nichola Sweeney (20) was in her bedroom with her best friend Sinead. Peter entered the room, took the knives from under his top and launched a violent assault on her friend Sinead, stabbing her so ferciously, over 20 times, that he broke one of the knives. He then lunged at Nichola and stabbed her 11 times, finally killing her by stabbing her in the heart. Sinead, despite her injuries had crawled downstairs and hidden in a toilet. Peter Whelan left the house, assuming she was dead. Sinead gave a perfect description to the police and he was arrested.