Murderer John Cooper is one of Wales' most notorious serial killers, but it took over two decades to bring him to justice.
The 76-year-old Welsh killer is currently behind bars in an undisclosed prison.
Luke Evans plays detective Steve Wilkins in the new ITV drama The Pembrokeshire Murders, based on the chilling true story of the serial killer's four double murders.
The killer was given four life sentences for a series of horrific murders that occurred in Pembrokeshire in the 1980s, following a cold-case review that began in 2005.
How did he manage to evade justice for over 20 years after the killings?
Cooper had a long history of crime, including 30 robberies and violent assault.
In 1998, he was sentenced to 14 years for burglary and robbery but was released in 2009.
Following a cold-case review which started in 2005, he was eventually arrested and convicted of the two double murders in 2011.
He was convicted for the murders of Richard and Helen Thomas, and Peter and Gwenda Dixon.
Cooper killed brother and sister Richard and Helen Thomas in December 1985.
Residents of Milford Haven were horrified when the bodies of the siblings were discovered in the remains of their farmhouse, which had been burned down by the murderer.
Cooper became known as the Bullseye Killer as he appeared on the ITV television gameshow on 28 May 1989, just four years after murdering Richard and Helen Thomas.
One month after his appearance on the popular telly programme, Cooper committed his second double murder.
He shot and killed married couple Peter and Gwenda Dixon after robbing them of £300.
Cooper was spotted using Peter's bank card at a cash machine soon after the brutal attack.
The series of horrifying killings became known as the Pembrokeshire Murders.
The serial killer infamously managed to escape justice for around two decades after the 1980s murders.
He was finally found guilty using advanced forensic techniques following an eight-week trial.
Cooper was given a life sentence on May 26, 2011, for the 1985 double murder of siblings Richard and Helen Thomas, and the 1989 double murder of Peter and Gwenda Dixon.