Durga Soren, the elder son of Jharkhand Mukti Morcha (JMM) chief Shibu Soren, died in his sleep in his Bokaro home on Thursday. He was 39.
Durga Soren was the national general secretary of JMM. His body will be cremated Friday in his native village Nemra of Ramgarh district.
He had fought for the Godda Lok Sabha seat and lost to the Bharatiya Janata Party candidate.
According to family sources, Durga went to sleep Wednesday night and didn't wake up. They got to know about his death when family members tried to wake him up. The body has been kept at the Bokaro General Hospital for post-mortem.
Shibu Soren and his second son Hemant were in New Delhi to attend the United Progressive Alliance (UPA) meeting on Wednesday. They arrived in Bokaro in a chartered plane Thursday.
The death of Durga Soren, the national general secretary of JMM, is a major loss to Shibu Soren, who is ailing. Shibu Soren had quit as chief minister in January and he lost his younger brother Shankar Soren in the same month. He underwent bypass surgery early this month.
Talking to reporters, Hemant Soren said: "When Durga died we were not at home."
Close family associates say that Durga had dinner with some friends on Wednesday night. He apparently suffered a heart attack early Thursday morning.
Doctors have however ruled out death due to kidney failure.
Durga, who was legislator from 2000-2005, believed that the Congress was responsible for the defeat of his father in the Tamar assembly by-poll, which forced Shibu Soren to quit as chief minister in January. Durga was apparently determined to oust the Congress from Godda, said a close associate.
Durga lost, but sitting MP Furkan Ansari of the Congress lost the election too. After the polls, Durga was sidelined both in the party and the family, the associate said.