In February 1976, a junior-level Dutch diplomat named Herman Knippenberg launched a mini-investigation into the tragic case of two travelers: 29-year-old Henk Bintanja and his fiancee, 25-year-old Cornelia "Cocky" Hemker.
As the Bangkok-based professional eventually learned, the young couple had visited Charles Sobhraj, a notorious con man and serial killer preying on Western tourists, shortly before they died. So, what happened next? Where is Herman now?
Herman Knippenberg learned about Charles Sobhraj's activities in the late 1970s.
Herman set out on a quest to dig up more information about Sobhraj's highly suspicious undertakings after learning about the heartrending case of Henk and Cornelia, whose strangled and burned bodies were found and falsely identified in December 1975.
Herman and his then-wife, Angela Kane, were determined to unveil the killer. A new series on Netflix, titled The Serpent, charts their attempts to produce incriminating evidence against Sobhraj.
Herman reportedly left Bangkok in 1977, just a year after Sobhraj was put on trial. It is believed that he continued to work as a diplomat in countries like the U.S., Indonesia, Austria, Luxembourg, Greece, and New Zealand up until his retirement in 2003. He still keeps an archive of Sobhraj-related materials in his home in Wellington, New Zealand.
"I couldn't forget him, it was like having malaria. Every couple of years or so something would happen that would draw me back into the case again," Herman previously told Nepali Times.
Herman and Angela divorced in 1989. Herman went on to remarry a woman named Vanessa. Angela, too, is married to someone else, though further details about her new partner are hard to come by.
Herman says 'The Serpent' provides an accurate portrayal of his life experiences.
"I think that Billy Howle [did] a fantastic job. It was so real at times. In some of the scenes which I saw, I was absolutely gripped myself, and I had to make up my mind whether indeed it was as Billy played it, or, let's say as I had experienced it. It came dangerously close," Herman explained during a recent appearance on Loose Women.
Angela raised a few objections in a recent interview with Daily Mirror, however.
"I was never the dutiful diplomat's wife. I had my own experiences and I could be difficult and that part of me was not properly captured. Herman liked a sounding board and as the case went on, he relied on me," she told the outlet. "I would have liked certain things to be different and I have told them that but it is what it is. They can take certain liberties and there is nothing I can do about it."
The creators of The Serpent made strong efforts to cast actors with similar features to the real-life people whose stories they were aiming to tell. As the former UN Under-Secretary-General told Daily Mirror, Angela's character in the show was an exception.
"Ellie [Bamber] plays me as a blonde and I didn't have long hair at the time and I was never blonde," she said. "I thought Ellie was very young for the role – I was only three or four years older but I'd been around a bit. I didn't think it was fair."
Stream The Serpent on Netflix.