An elderly man died of cardiac arrest, the locals alleged, triggered by his wife's name not being included in Assam's National Register of Citizens or NRC.
Muhibur Rahman, 65, was a farmer in a village in Karimganj district. He and his seven children were on the final draft of the citizens' list, but his wife Renu Bibi's name was missing, locals said.
Mr Rahman had gone to the local NRC Seva Kendra on Monday to figure out why his wife had been left out of the list despite submitting a land document. The official reportedly told him to submit any other document.
As he was returning from the centre, he had a heart attack. He was shifted to a hospital where the doctors declared him brought dead.
The residents of his village are demanding compensation for the bereaved family.
The NRC is an exercise aimed at identifying genuine Indian nationals living in Assam, witness to an influx of people from Bangladesh since the early 20th century.
The draft list published on July 30 excluded over 40 lakh people, creating a huge political controversy.
There have been several incidents of alleged suicide in the state after the draft list was published. In most cases, family members have claimed mental stress to be the reason for committing suicide.