A 36-year-old former insurance agent was jailed for two years and five months by Singapore District Court on Tuesday after pleading guilty to sending threatening messages. Using the names of fictional characters, the threats were sent to 33 people who had cancelled insurance policies or failed to keep appointments with him.

The accused named Ye Lin Myint, a Myanmar national with Singapore permanent residency, pleaded guilty to five counts of criminal intimidation and eight counts of harassment. Another 30 charges of similar offences were taken into consideration by the court during sentencing, the Shin Min Daily News reported.

The court heard that the former Prudential agent was frustrated by neighbors and clients who had either cancelled policies taken out through him, or not turned up for scheduled appointments.

To vent his anger, he used a portal called Protonmail, which does not require users to key in correct personal information, to create email accounts under the names “Lord Voldemort” – the main antagonist from the Harry Potter novels – and “Dr Bruce Banner”, who is the Marvel Comics superhero Hulk’s alter ego, in July 2017.

Between August and September the same year, the accused started to send threatening letters and emails to a total of 33 people, noting that harm would befall them and their families if one Bitcoin, which was equivalent to about S$6,600 (US$4,902) at that time, was not transferred to his Bitcoin wallet.

The police managed to identify the perpetrator through DNA testing from saliva on the back of postage stamps on threatening letters.

On Tuesday, District Judge Marvin Bay said the accused’s offences showed a “remarkable degree of planning”, despite the fact that no victims had given in to his demands.