The mother of the Bihar police officer allegedly lynched by a mob at a village in North Dinajpur died of cardiac arrest on Sunday after knowing that her son was no more.

Urmila Devi, 70, had not been keeping well for some time, and the arrival of the body of her eldest son, Ashwini Kumar, at their village in Jankinagar in Purnea district proved to be the last straw.

Kumar, 50, had been posted as the Kishanganj station house officer (SHO), around 390km northeast of Patna. He was killed on Friday night at Panthapara village in North Dinajpur in neighbouring Bengal where he had gone with a police team to probe a motorcycle theft case. Three persons have been arrested in connection with the killing.

The funerals of Kumar and Urmila were conducted together at the local cremation ground. People from the area, public representatives as well as senior administrative and police officers were present.

“My father was an honest and brave police officer. We believe he has been killed as part of a conspiracy hatched by some police personnel and other people. The CBI should probe the incident because I do not have faith in the local police,” Kumar’s daughter Nancy told reporters.

Purnea range inspector-general Suresh Chaudhary has suspended an inspector and six constables accompanying Kumar for dereliction of duty. They had been armed but allegedly fled, leaving Kumar at the mercy of the mob.

Chaudhary announced that all police personnel posted in the Purnea range would contribute a day’s salary to Kumar’s family. The total amount is expected to be around Rs 50 lakh.