The third episode of The Serpent left viewers particularly "terrified" when it aired on Sunday evening.
The BBC drama, which stars Jenna Coleman and Tahar Rahim, is becoming increasingly intense as the series progresses, and many fans took to social media to share their thoughts.
One person wrote on Twitter: "Not sure why I'm putting myself through #TheSerpent. Terrified though episodes one and two, heart pounding through episode three."
WATCH: The Serpent official trailer
Another said: "Practically having palpitations after episode three of #TheSerpent, which was so tense that I didn't think about Covid for an entire hour."
Plenty of other fans agreed, with a third stating: "Episode three is the best episode in the role series. Tension is ridiculous. #theserpent," while a fourth tweeted: "I'm still recovering from episode three. Quite literally heart-poundingly good. Tahar Rahim is scary."
The third instalment in the drama, which tells the true story of serial killer Charles Sobhraj who went on a murder spree in the 1970s in many Asian counties, took a turn when a young Frenchman named Dominique become entrapped in Charles' devious plans.
Episode three focused on Dominique's entrapment by Charles
The backpacker is initially charmed by the conman and murderer and the two became friends, but then Charles subsequently poisons Dominique under the guise of "medicine." When he sees the effect the 'medicine' has on a their pet monkey, Dominque catches on and makes a run for it – but not without some difficulty.
The Serpent is based on true events. Back in the 1970s, notorious killer, Charles Sobhraj was on the loose, escaping authorities and police investigation. He and his girlfriend, Marie-Andrée Leclerc (played by Jenna Coleman), travelled across Nepal, Thailand and India in 1975 committing a series of crimes on what was known as the 'Hippie Trail'.
He was Interpol's most wanted criminal for a period of time in the 70s, and was being hunted down by Dutch diplomat Herman Knippenberg. Soon after Herman began investigating him, Charles was arrested in India in July 1976 and was sentenced to life imprisonment, and remained incarcerated until 1997. After a suspicious return to Paris where he courted his infamous notoriety, he was reprimanded again, and the now 76-year-old is still serving his sentence in prison to this day.
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