Richard Chamberlain went on air with ITV's This Morning, where he spoke about his mum, Elaine, 76, who was convinced she was going to marry one of the men and had purchased a wedding dress and marital rings in the run-up to her death.
He said the romance scammers 'ruined' his mum's life by fleecing her of her finances and destroying their relationship.
Richard, who works as a retail manager, told This Morning hosts Phillip Schofield and Rochelle Humes, recounted the moments one of the scammers video called his mum, just hours after her death.
He said: "A few minutes after I walked into my mum's house, her phone was ringing and I picked her phone up. It was a FaceTime call and I answered the call.
"There was an African gentleman on the other end of the phone asking for Elaine, and I said, 'Elaine's not here'. I said, 'Elaine's dead' and he said, 'Elaine's dead?' I said, 'Yes'' and, 'You guys have killed her’ and I just cut the phone off."
Elaine's tragic story made headlines last year when Richard revealed that the scammers ‘stole her dignity' by fleecing her of her life savings and destroying her personal relationships.
Richard said his mum, who had arthritis, started deteriorating following the death of her partner of 31 years, Danny, in 2013.
He added: “When he died, mum was lost. He was the love of her life.”
‘Ruthless’ and ‘heartbreaking’
The first sign of trouble came in 2019 when Elaine said she had met a man online but became 'vague' when asked about him.
Elaine, a former dinner lady, was led to believe the person she was talking to was a white man in his 60s, working abroad as a diver on a ship.
Richard said Elaine did not believe him when she was told she was being scammed.
He said: “I told mum, ‘You’re being scammed’, but she would just say, ‘No, I’m not, no, I’m not’.”
Richard said Elaine became aware the man she was talking to was not who was in the picture and instead was a young black man.
However, he said, ‘it did not matter to her’.
Describing the fraud as 'utterly ruthless' and 'heartbreaking', Richard urged the people to look out for the tell-tale signs.
He said: "If it's happening to your parents, whether it be your mum or your dad, just look out for the tell-tale signs, just help them as much as you can.
Action Fraud said romance scams involve people being duped into sending money to criminals who go to great lengths to gain their trust and convince them that they are in a genuine relationship. They use language to manipulate, persuade and exploit so that requests for money do not raise alarm bells.
If you think you or your loved one is being scammed, please contact your bank immediately and report it to Action Fraud on 0300 123 2040 or via actionfraud.police.uk