The post was shared by AfriForum, and within hours the man was arrested at the complex in Brixton, Johannesburg, where he was living and working.
Sergison, 49, told The Times in the UK: “I couldn’t believe it — if I saw it happen in a film I would’ve said it was too cheesy.
“I was in the garden centre buying lavender, because it was Chrissy’s anniversary and it was her favourite plant, when I got a call to say he had been arrested.
“I almost got him once before with a honey trap. I remember sitting on the couch on a Sunday afternoon and engaging with him over Facebook — my husband and I came up with a back story. I told him I was a stewardess as it meant I wasn’t always contactable.
“He was on the run so I knew his guard was up. At first I befriended his friends, to allay suspicion, before befriending him. He was using a slightly different name to his real name and was a member of dating groups. He wrote some horrible things, like ‘I need a woman, any age, any size’.
“He wanted to speak to me on the phone so I spoke to the SA police and they got a female officer to contact him. But it took time and it didn’t work out.
“I kept going because Chrissy deserved it. She was such a wonderful woman. She was so kind, she had been a teacher all over the world and was full of tales. She was tying up loose ends in SA and was hoping to come back to England or France.”