A student who fatally poisoned his flatmate in what he alleged was an April Fool’s Day prank was executed in China after insisting the killing was intended as a joke.

In 2013, Lin Senhao, then a 27-year-old postgraduate at Fudan University’s Shanghai Medical School, stole a liver-damaging poison and probable carcinogen from his institution’s laboratory and placed it in his accommodation’s water dispenser.

Lin’s flatmate Huang Yang was poisoned after drinking the water, and succumbed to multiple organ failure a fortnight later, according to AA.

The court determined Lin poisoned Huang driven by resentment and envy after the latter secured admission to the postgraduate programme. Lin had been compelled to withdraw for personal circumstances.

Lin utilised N-nitrosodimethylamine, maintaining it was merely intended as a prank. He faced trial between 2013 and 2015 and was executed on 11 December 2015. Lin insisted he only wished to make Huang unwell, not fatally harm him, reports the Daily Star.

Lin started living in dormitory room 421 in August 2010 before Huang arrived a year afterwards – the duo allegedly had a difficult relationship.

On 29 March 2013, Lin discovered Yang and his companions were planning to carry out an April Fool’s Day prank.

At the Intermediate People’s Court, Lin testified that on 31 March 2013, he requested the poison from his classmate Lü Peng, claiming he required it for an experiment.

Lü handed Lin the key to the laboratory, and Lin retrieved a bottle containing 75 ml of a reagent and a syringe filled with the poison — which triggers the rapid deterioration of the liver. Lin administered a dose ten times the lethal amount for humans.

When Huang fell ill, investigators began probing how he had been poisoned. By April 12, Lin had been identified as a suspect and taken into custody by police.

Huang died four days later after all attempts to save him proved unsuccessful. His liver, kidneys and lungs had all failed.

Shanghai High People’s Court forwarded their death penalty ruling to the Supreme People’s Court for ratification. Eight months later, Lin’s death sentence was formally approved.

“The defendant Lin Senhao committed intentional homicide by poisoning due to trivialities. The method was ruthless, the harm to society was great, the crime extremely serious,” the court stated.

Prosecutors argued Lin murdered Huang over a grievance stemming from “trivial daily matters.”

Lin’s father, Lin Zunyao, said “my heart breaks, I can’t think now”, upon being informed he must visit his son before his execution. His son was put to death by lethal injection on December 11, 2015.

The case drew comparisons to a 1994 incident involving a student at Tsinghua University in Beijing, who was allegedly poisoned with thallium — a toxic chemical used in rodent and insect poisons — by classmate Sun Wei while the pair were studying chemistry.

The victim, Zhu Ling, survived the poisoning but sustained severe brain damage. Even at 40 years old, Zhu remained largely bed-ridden, virtually blind and with the mental capacity of a 6 year old child. He was previously a keen swimmer and accomplished musician.