John Boyle is terrified the 'Wild Horses' singer could be murdered by an obsessed fan like the Beatles star, and has pleaded for an increase in security after Susan found an intruder in her home on Tuesday evening (26.01.10).
He told The Sun newspaper: "I am very upset about the lack of security. The family have told them several times that vast improvements need to be made to avoid something like this happening.
"This is the second time something has happened to Susan at her home and it is extremely worrying. Susan is a massive world star and needs better protection. You look at what happened to John Lennon in New York - it's really worrying."
John died in 1980, after being shot by deranged fan Mark Chapman outside his apartment building in New York.
Susan was returning home with a female pal after she had spent the day in a music studio in London, recording her vocals for Simon Cowell's Haiti charity single.
Despite being scared about the intruder, the 48-year-old star is adamant she won't let the incident drive her out of her home in West Lothian, Scotland.
She said: "I'm not going anywhere - nobody's pushing me out of my house. I'm absolutely fine but it was very concerning for everyone. I think he got more of a scare than I did because he ran off.
"The matter is in hand and the police have been excellent."
Since the break-in, music mogul Simon Cowell - who does not manage Susan but has kept a close eye on her since she appeared on 'Britain's Got Talent' - has arranged a team of minders to watch over her.
It is believed Susan is worried the man was the same one who tried to break into her house on December 21.
At the time the singer - who lives at home with her cat Pebbles - was so frightened she was forced to ring emergency services.
A source said: "Somebody was intent on getting in and didn't care that she was in at the time. She's worried it's the same man this time too. It's too much of a coincidence."