For years, there was little outcry over the length of his hefty prison sentence, largely due to the shadow of suspicion that had long followed him. Many believed he was connected to a notorious crime spree that had haunted the streets of Boston.

During an unsettling 18-month period, a serial killer brutally took the lives of 13 women, strangling them in their own homes. The assailant remained an enigma, with the city gripped in fear as the killer continued to elude capture.

One chilling incident involved a woman who was sexually assaulted by the assailant. Before fleeing the scene, he offered a disturbing apology, saying, “I’m sorry,” leaving her and the authorities with more questions than answers.

At the time, Albert DeSalvo had been dismissed as a suspect in these infamous Boston Strangler murders. The police had moved on, and the case seemed to grow cold with each passing day.

However, the case took a dramatic turn when F. Lee Bailey, the lawyer representing George Nassar, DeSalvo’s cellmate, stepped into the spotlight. Bailey revealed that Nassar had alleged DeSalvo confessed to the murders while they were imprisoned together.

Nassar had claimed DeSalvo had confessed to the spree of murders.

Under hypnosis, DeSalvo told police of the murders he had committed.

He later confessed to police while not hypnotised.

But because of the inconsistencies of his confession and the lack of any physical evidence, he was never charged.

Nevertheless, he would be jailed for life.

But a month later, DeSalvo managed to escape a hospital for the criminally insane.

In a note left on his bunk, DeSalvo told the warden he wanted to escape to draw attention to the poor conditions in the hospital.

He turned himself in three days later and was taken to a maximum security prison.

Six years later, he was found stabbed to death.

No-one was convicted for the crime, but it is believed he was killed for selling drugs for cheaper than the syndicate price in the prison.

Over the years, sceptics began to doubt that DeSalvo was even the Boston Strangler.

A more likely culprit was cellmate Nassar, according to their prison psychiatrist Ames Robey.

Robey speculated DeSalvo took credit for the murders out of a perverse desire for notoriety.

But decades later, the truth was confirmed.

DeSalvo’s body was exhumed to confirm the results.

But whether DeSalvo was responsible for all the cases remains uncertain.