The murders of Tony Marrocco and Paul Sandham shocked the community in 1995.
Antonio Marrocco - known as Tony - was found beaten to death at his garage TM Motors on Northgate, Morecambe, on January 23, 1995 after family members raised the alarm.
His colleague Paul Sandham was found stabbed to death in a field off Powder House Lane the following day.
The hunt for their killer turned into one of the biggest and most complex criminal cases in local history.
Detectives believed the killer had asked Paul to take him for a test drive, before stabbing him to death and returning to the garage to murder Tony.
Police identified 24-year-old Terry Clifton, a Londoner by birth who had moved to Morecambe and attended Morecambe High as the suspect in the murders.
Clifton was found guilty of both murders, and it took nine prison officers to drag the struggling killer into court to be handed his life sentence.
Now the case is to feature in a new episode of the CBS series Murder by the Sea.
The series looks back at some of the most high profile crimes committed in British seaside resorts.
CBS spokesman Steph Faber said: "Some of the most strange and terrifying murders ever recorded in British criminal history have taken place at our famous seaside resorts; the grand hotels playing host to some of the deadliest murderers imaginable, and the seafronts doubling as stalking grounds for the most wicked of serial killers.
"This new and exclusive six-part series, presented by renowned true crime author Geoffrey Wansell, explores why many British seaside towns have dubious reputations for hosting the most remarkable crimes."
The show screens at 10pm on Monday on CBS Reality.