Most of us have heard the name of Charles Sobhraj, the serial killer who murdered at least between 12 to 24 people between 1963 and 1976, who is in the news recently due to the BBC-Netflix series The Serpent based on his life. However, it is significantly less known how different people played a vital role in his conviction. One of the most important persons, in this case, is a Dutch diplomat named Herman Knippenberg. Over a period of time, Knipperberg collected a lot of evidence against Sobhraj, and when the time came, his efforts and documentation helped in his conviction to a large extent. This is the story of the man, the Dutch diplomat, who sent the Serpent behind bars.

The dark day of 1976

Herman’s involvement in the case began in 1976 when he received a letter in February about two Dutch backpackers who went missing in Bangkok. During that period, as the world was not yet developed enough to share information about criminals with a blink of an eye, it was much easier for the likes of Sobhraj to change identity and roam across the globe without fear of arrest. Bangkok was no different, and it used to be a less connected city at that time. In the lack of communication devices that backpackers use nowadays, sometimes travellers would go unchecked for weeks and even months.

The case of two Dutch backpackers was Herman’s first encounter with the horrifying stories of Sobhraj. The letter that Herman received was from a man who was looking for his sister-in-law and her boyfriend, identified as Henricus Bintanja and Cornelia Hemker. According to the letter, they had been writing to the family at least twice a week while travelling Asia. However, for six weeks, they did not hear from them that raised concerns.

Then 31-years-old Knippenberg was working as a junior diplomat at the Dutch embassy. He had been living in Bangkok for some time with his wife, Angela. When Herman read the letter, a story that he read about the discovery of charred bodies a few weeks back started coming back to him. The bodies were found on the roadside near Ayutthaya, which is located around 80 KMs north of Bangkok. Initially, Police thought they were missing Australian backpackers, but later they were found to be alive. Connecting the dots, Herman figured they might be the missing Dutch backpackers.

One of the main reason he took an interest in the case can be asserted from one of his interviews that he gave to Daily Mail. He said, “I’d been travelling in my 20s, and I knew that people like Henk and Cornelia would keep in touch.” He immediately got hold of a Dutch dentist based in Bangkok for help in identifying the burnt bodies. He got the dental records of the missing couple and, with the help of the dentist, matched them to the bodies at the police morgue. Herman said, “What shocked me the most was when the pathologist at the mortuary told me there was soot in their lungs, which indicated they had both been set alight when they were still alive.”

While trying to what happened to the couple, he remembered a story that his friend Paul Siemons, an administrative at the Belgian embassy, told him about a French gen dealer identified as Alain Gautier who had possession of a large number of passports in his Bangkok apartment. The connection between the Dutch couple and Gautier became stronger when the couple’s parents told Herman that they were told that the couple had met a gem dealer named Alain Gautier in Bangkok. Those passports allegedly belonged to the missing persons who were believed to be murdered. Two of the passports were Dutch. However, Siemons refused to tell Herman about his source of information.

When Herman first heard the story, he thought his friend was crazy, but now he could link that story to the Dutch couple. Later, he discovered that Alain Gautier was, in fact, one of the many aliases that Sobhraj had used throughout his life. For a long time, Herman kept investigating him by his alias that was Alain Gautier. It was later revealed that while Sobhraj, the conman and serial killer, had been befriending travellers only to drug and rob them. As the security was not that perfect those days, he would take the victims’ identity and travel across Asia like a free man.

The hunt of the Serpent

After a day of his trip to the morgue, Knippenberg decided to call Siemons and asked him to tell the source of the story about the gem dealer. After some persuading, Siemons told him that Nadine Gires, a Frenchwoman who lived in the same apartment building as Sobhraj, used to introduce clients to him.

When Gires met Herman, she revealed how other people who worked for Sobhraj fled after discovering the collection of passports belonging to the missing persons. They were afraid that he would kill them too. She told Herman that she remembered seeing the Dutch couple at his home. Without wasting any time, Knipperberg alerted the authorities. If he had followed the rules, his role would have ended with Thai authorities taking over the case, but Herman continued investigating the case independently.

When the Serpent slipped out of the fingers of the law

On March 11, Gired told Knippenberg that Sobhraj and his girlfriend Marie-Andrée Leclerc alias Monique were planning to leave for Europe. He informed the Police, and officers stormed Sobhraj’s apartment. Though he was taken for questioning, he was well prepared. According to the biography of the killer written by journalists Richard Neville and Julie Clarke, “The Life and Crimes of Charles Sobhraj”, he used one of the victim’s passport. He had replaced the photo with his own and identified himself as an American citizen. He was released from custody.

Later that night, Gires called Knipperberg and informed him that one of Sobhraj’s housemate had invited her to the apartment as he wanted to talk. There was a danger to her life, but if she did not go, he might find out Gires was the one who leaked the information about the passports. When Gired was at the apartment, she was alone for a few moments and used the time to slip some passport photos she noticed into her bra. Those photos gave more information about one of his victims. The very next morning, Sobhraj and his girlfriend left Thailand forMalaysia.

When Herman came to know his true identity

After Sobhraj escaped, Knippenberg faced the wrath of the Netherlands officials, who were frustrated at the Thai police’s inaction. He was sent to three weeks’ leave. Before he left for the holiday, he and his then-wife Angela compiled a cache of documents, now known as Knipperberg cache, and dropped them across Bangkok in different embassies. Knippenberg couldn’t let go of the case even though his superiors had told him to forget about it. He said, “The more I saw it, the more I knew I had to follow this. The ambassador told me to stop, and he even sent me on leave at one point. But I wouldn’t give up on them, even though I knew I was putting my career in danger.”

After returning from his leave, he got a call from the Canadian Ambassador, who informed him about the visit that Canadian Police paid to the parents of Sobhraj’s girlfriend. They told the Police that their daughter had been travelling with her boyfriend and had left an emergency contact. The number belonged to Sobhraj’s mother, who finally revealed the true identity of Sobhraj.

Sobhraj’s filthy lair

Within few days, Gires called Herman and informed him that Sobhraj’s landlord was planning to rent out the apartment where Sobhraj lived, and his belongings would be thrown out. Knippenberg immediately formed a team and reached to the apartment to collect any possible evidence.

Knippenberg, in his statements, mentioned that the apartment was seedy and filthy. He found 5 KG of medicine and three industrial-size cartons of liquid drug that can be used as a laxative or a “chemical straitjacket.” They also got hold of Dutchwoman Hemker’s coat and handbag in the apartment.

On May 5, 1976, on the orders of the Dutch ambassador, Herman shared the story with the press, and within days, Bangkok Post printed a front-page story titled “Web of Death”. The story became a topic of discussion in Thailand that forced the Thai authorities to notice the issue. They issued an Interpol notice which led to the arrest of Sobhraj on July 5, 1976, in India.

Sobhraj – The bikini killer

Sobhraj was born in 1944 in French-administered Saigon to a Vietnamese mother and Indian father. According to biographers, he had a difficult childhood. His parents had split up few years after his birth. His father rejected him, and his mother married a French soldier, after which the family moved to France.

Those who knew Sobhraj painted him as a handsome and charming conman. He had a long list of girlfriends and sometimes shuffled between many at the same time. In 1963, he was jailed for the first time for burglary. During his time as a criminal, he had escaped from prison in several countries, which led to the name “the Serpent”.

Sobhraj never revealed why he started killing. He had admitted to at least 12 killings between 1972 to 1976. He said to have killed the alleged victims by drugging them until they overdosed, drowned some of them and in some cases stabbed them and set them on fire. He had thrown some burnt bodies by the roadside. Those bodies, when discovered, were burned beyond recognition. It is unknown how many people he had killed. He was convicted for only two killings during his life, for which he is facing life imprisonment in Kathmandu, Nepal.

The first person he killed was a Pakistani taxi driver in 1972. He had killed six victims in Thailand, including an American tourist, two French nationals, a Dutch couple and a Turkish man. The American woman he had killed was found in a swimsuit floating off Pattaya beach. The case earned him the nickname “the Bikini Killer.”

Sobhraj’s arrest in India

In Spring 1976, he fled to India after the stories of bikini murders started to make the headlines. He was on Indian authorities’ radar over the international arrest warrant. He was arrested for drugging a French tour group in Delhi in July 1976. Notably, the Indian Police also charged him for the murder of an Israeli man in Varanasi and a French tourist in Delhi. However, the charges of two murders were overturned on appeal. He was found guilty only of the robbery attempt and was sentenced to 12 years of jail in Delhi’s Tihar prison.

Sobhraj’s luxury stays at Tihar

According to Sunil Gupta, former superintendent and legal officer at Tihar, Sobhraj enjoyed his stay at Tihar. He would get food based on his preference and often get conjugal visits that other inmates could not afford. Gupta wrote a memoir titled “Black Warrant: Confessions of a Tihar jailer”, in which he said how he would roam freely while other inmates had to stay in their wards.

Sobhraj used his knowledge of the law for drafting court petitions for wealthy inmates and used the money for his lavish lifestyle by bribing the guards. It was alleged that he had secret recordings of senior prison officials that could lead to their conviction under corruption charges. It helped him keep up with the lifestyle in jail.

According to Bangkok-based journalist Alan Dawson who interviewed him in Tihar in 1984, he had a “suite of three cells”. Everyone respected him and the visitors who came to meet him. It was unclear who had instructed them to be nice to people who came to meet him, Charles or the higher officials.

Escape from Tihar

On March 17, 1986, Sobhraj escaped from Tihar. Gupta ran to the prison when he was informed about the escape. He found out that Sobhraj offered gatekeepers sweets laced with sedatives on the pretext of his birthday. Over a dozen prisoners, including Sobhraj, escaped that day.

When the news of his escape made international headlines, Knippenberg was informed by his program adviser at Harvard University, where he was studying for a master’s degree. She asked him to go underground, but Herman was adamant as he believed Serpent would not come after him. He was right, and Sobhraj was arrested on April 6 while enjoying his time in Goa on his 42nd birthday. He was sent to jail for an extended time, putting an end to the statute of limitations for his extradition to Thailand.

It is believed that it was his plan to escape from prison and get re-arrested so that his jail term is extended and he can’t be extradited to Thailand. Because his jail term was 12 years was getting over soon and within the statute of limitations, which he would be extradited to Thailand after his release, where he would be executed for the crimes he committed there. His plans worked, as his jail term was extended by 10 years, exceeding the statute of limitations for extradition to Thailand.

When he was released from Tihar in 1997, the Indian govt allowed him to go back to France as at that time there was no extradition request for him from any county. In Franch, he hired a publicity agent and charged large sums of money for interviews and photographs. He once sold book and movie rights of his story for $15 million to an unnamed French actor-producer. However, no film was released. Several books and television series did make it to the market.

The conviction

In 2003, Knipperberg received a call on his first day of retirement about the arrest of Sobhraj in Nepal. He fondly remembered, “Yes. It was a Saturday morning on the 19th of September 2003. A cool spring day in Wellington. It was the first day of my retirement, and I was looking forward to a breakfast of pancakes. That’s when the phone rang.” The serpent was being charged with the 1975 murder of a tourist in Kathmandu. It is unclear why he travelled to Nepal as it was the only country left in the world where he was still a wanted man. Sobhraj denied visiting Nepal before during questioning. This is where Knippenberg made a huge entry in the story.

At first, he could not believe what he was hearing. He said, “Don’t be ridiculous, he’s busy charging gullible Americans $5000 for the dubious privilege of having lunch with a serial killer in Paris.” He dug out the six boxes filled with evidence he had collected over time. He remembered correctly that his girlfriend told during questioning after her arrest in July 1976 that they spent time in Nepal. He had the documents and forwarded them to the FBI. In a statement, Knipperberg said, “I think it goes too far to say that I was directly responsible for his conviction in Nepal. Though my efforts indicated to Nepal police what there was and where to look for it.”

Sobhraj was charged with the 1975 murder of an American tourist Connie Jo Bronzich. His lawyer approached United Nations Human Rights Commission as his arrest allegedly breached his human rights. He was detained for over 25 days without a lawyer and then sentenced in August 2004. He was not allowed to call his own witnesses or hear evidence presented against him. In 2010, Anthony Cardon, then officer-in-charge of the office of the UN High Commissioner for Human Rights in Nepal, wrote that everyone should be afforded human rights no matter how notorious their alleged crimes are. However, his statement made no difference, and Sobhraj remained in jail.

In 2014, he was sentenced to 20 years for the murder of Canadian tourist Laurent Carrière. The case was reopened in 2013 as the prosecutors were afraid he would appeal for an early release on the pretext of old age.

While many cases remained unsolved, he is spending his time in jail. Sobhraj made headlines in 2008 when the 64-year-old jailed killer married the 20-year-old daughter of his lawyer Nihita Biswas. She was his translator throughout the case. In an interview with Times of India, she claimed he was innocent, and there was no evidence against him.

The fear that Sobhraj may be a free man soon

There is a strong possibility that the Nepalese government let Sobhraj go based on his old age. A few years ago Nepal made changes to its jail manual which calls for the release of inmates above 72 years of age. 76 years old Sobhraj is eligible for release as per this rule, but Nepal govt has not released him. He has already filed pleas with courts for his release.

Knippenberg still remembers how injustice overpowered democracy in this case. He said, “I was confronted with a situation in which innocent people were losing their lives, and nobody lifted a finger. I saw that as the complete failure of democracy.”

Knippenberg will always be a hero who got Sobhraj arrested

Knippenberg has been deemed as a hero in the BBC/Netflix drama titled The Serpent as he helped get Sobhraj arrested in two countries. It was him who kept all the documents in perfect condition with him for years. Though his investigation was not high-voltage drama full of real-life car chases or gunfights, the work he had done in collecting proofs against Sobhraj is commendable. He collected paper clippings, made notes, kept the possible evidence with him and above all remembered the details that led to the conviction of the Serpent.

The four boxes full of four boxes of material, including yellowed photographs, extensive witness statements and photocopies of embarkation cards, flight manifests and passports, were the proof that made it possible for the Nepalese government to throw the bikini killer behind bars. However, he does not see himself as the one. “I do not see any heroes here. It was a tragic misuse of the supremely gifted mind,” he said about Sobhraj.

In 2004, in an interview with Nepali Times, he said, “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.” For him, the case is still open as justice has not been served in many alleged murders by Sobhraj.