Fans knew that bigamist Mark (Maxwell Caulfield) was to be killed, but they had to wait until Thursday night to see which member of his horrified family did the deed.
James, whose character Ryan Lamb is reeling from the discovery that Mark is his father, said he wasn't surprised to learn that Natasha (Amanda Donohoe) was the killer.
He said: "I had a hunch it would be Natasha because she's the one that feels more betrayed by him than anyone else. He had two affairs with same woman behind her back and he's still married to her. He pushed her a bit too far."
Alice Coulthard, who plays Maisie Wylde, was also unsurprised Natasha was the murderer.
She said: "He put her in a position where her entire life was a lie and her entire family was destroyed, and rather than get over it he'd gone back to the other woman and was deceiving her and hurting her family again, and it led to her daughter almost sleeping with her brother. I don't think I was surprised. I think it's quite understandable how she could be driven to those extremes."
Alice doubts her own character would have been capable of the murder.
"She's always had things easy in life and when things go a little bit awry she finds it quite difficult to cope. I didn't think she had the strength of will deep down to do that."
:: James is shortlisted in the Newcomer category at the National Television Awards. Vote for him at www.nationaltvawards.com.