Dale Cregan was born on June 6, 1983, in Tameside General Hospital. His parents were Anita Marie Cregan and Paul Cregan, who worked as a tool setter in Manchester. Dale was the second of three children. He had an older brother named Dean and a younger sister. When Dale was young, his father left the family. After that, Paul Cregan remarried a former policewoman who worked for Greater Manchester Police.

Dale went to Littlemoss High School in Droylsden, Greater Manchester. He had some trouble at school and began dealing cannabis. He also developed a strong interest in knives. At one point, Dale lived in Tenerife with his sister for about eighteen months. When he returned to Manchester, he started collecting firearms, and he ended up owning around ten different weapons, including machine guns.

By the time he turned 22, Dale had started dealing cocaine. He claimed to earn around £20,000 a week from his illegal activities. However, he told others that he worked as a plasterer. Cregan became known as 'One Eye' because he was missing his left eye. It is believed he lost the eye in a fight in Thailand, but the exact circumstances are not clear. During his trial, he had to remove his false eye to show police officers that he was not hiding anything.

Cregan’s first known murder occurred on May 25, 2012, when he walked into the Cotton Tree Pub in Droylsden and shot 23-year-old Mark Short in the neck. The attack, which left three others injured, was part of a long-standing feud between the Short and Atkinson families. Despite being arrested and questioned in June 2012, Cregan was released on bail due to insufficient evidence. Less than two months later, on August 10, 2012, he returned to escalate the feud.

That morning, Cregan arrived at David Short’s home on Folkestone Road East in Clayton, Greater Manchester. Armed with firearms and a military-grade hand grenade, he gunned down David Short before throwing the grenade at the victim’s body—marking the first known grenade killing in the UK. Later that day, Cregan attempted a second grenade attack at a different address in nearby Droylsden, but no one was harmed in that incident.

As the manhunt intensified, Cregan remained at large for over a month. On September 18, 2012, he lured two female police officers, PC Nicola Hughes (23) and PC Fiona Bone (32), to a home on Abbey Gardens in Mottram, using a bogus report of a burglary. When they arrived, he ambushed the officers with a hail of gunfire, firing at least 32 rounds from a Glock pistol, and then threw another grenade at their bodies. The killings were brutal and unexpected, targeting unarmed officers in a routine domestic call—a rarity in British law enforcement.

Cregan walked into Hyde police station less than an hour later, telling officers: “I’ve done two coppers.” He claimed his motive was retaliation, alleging that police had been “hounding” his family, though investigators and superiors deemed his reasoning to be manipulative and opportunistic.

He was swiftly charged with four counts of murder and four counts of attempted murder, and remanded in custody pending trial. While he initially denied the police killings, in February 2013, he confessed in court to murdering both officers, as well as the Short father and son. His confessions followed what he called a "final night of freedom," during which he drank beer and smoked cigars.

Dale Cregan’s trial began on February 4, 2013, at Preston Crown Court, with nine co-defendants charged with related crimes. Throughout the proceedings, Cregan appeared increasingly erratic. On February 12, he pleaded guilty to murdering PC Nicola Hughes and PC Fiona Bone. On May 22, he also admitted to the murders of Mark Short and David Short.

The trial concluded on June 13, 2013. Cregan was sentenced to life imprisonment with a whole life order, meaning he will never be released. He was also cleared of the attempted murder of Sharon Hark but convicted of multiple other attempted murders linked to the feud.

Following his conviction, Cregan was briefly held at Full Sutton Prison, where he went on a hunger strike in protest of prison conditions. In September 2013, he was transferred to Ashworth High-Security Hospital, a secure psychiatric facility. Reports from 2018 revealed that Cregan had access to snooker and tennis and was boasting about his fitness regime, leading to his return to prison custody in March 2018.

In December 2024, both Hughes and Bone were posthumously awarded the Elizabeth Emblem, a royal recognition for public servants who die in the line of duty. In April 2025, police recovered one of the Glock pistols used in the Short murders during a raid on a drug gang safehouse in Moss Side, potentially linking Cregan’s network to further criminal activity.