Three sisters, aged 16, 14 and 12, died by suicide after allegedly jumping from the ninth floor of their apartment building in Ghaziabad, Uttar Pradesh, Indian media reported on Wednesday.

According to Hindustan Times, police said the girls were highly addicted to an online Korean task-based mobile game and had developed an intense obsession with gaming.

According to Assistant Police Commissioner Atul Kumar Singh, the incident occurred at around 12:30 a.m.

“All three were with their mothers. After some time, they went to the puja room and locked it from inside. They then used a chair to jump out of the window one by one,” he said, adding that they died on the spot.

Security guards and residents alerted police after hearing the noise of the fall. The bodies were later sent for post-mortem examination, the newspaper reported.

Police said the sisters lived with their father, a forex trader, and their mothers. The eldest was from his first marriage, while the younger two were from his second marriage.

Investigators said the girls had left behind diary notes apologising to their parents and expressing their inability to quit the game. They also drew crying caricatures and referred to themselves as “Korean princesses”.

“They believed they were Koreans, not Indians, under the influence of the game,” Singh said.

Police added that the sisters had adopted Korean names, stopped attending school two years ago, and were not attentive to their studies. The eldest was still enrolled in class four.

Authorities said the addiction worsened after the Covid-19 pandemic.

Family members were aware of their gaming habits and had repeatedly confiscated their mobile phones, but the girls would retrieve them.

“They followed the same routine and even went to the bathroom together. Their diary contains detailed accounts of their lifestyle and obsession,” Singh said.

Police have seized the girls’ mobile phones and are analysing their contents to determine the role of the online game in the tragedy.