Lalu's wife and former Bihar chief minister Rabri Devi said that Gangotri Devi prayed for the entire day when the court was set to announce the sentencing for the RJD chief.
"She spent the entire day praying for the release of her brother. When she learnt that he was sentenced to jail for a long period, she was shattered," Rabri said.
Gangotri Devi was nearly four years elder to Lalu. She had not been keeping well for some time.
Lalu's family is trying to get a parole so that he can attend the last rites of his sister. His son Tejashwi Yadav said the family had tried to communicate the news of Gangotri Devi's death to Prasad through the prison authorities in Ranchi.
He, however, said that his father might not be able to get parole in time, due to the legal procedure involved.
"As of now, we are making arrangements to take the body to her village home, where the last rites will be performed," Yadav said.
Lalu was on Saturday sentenced to three-and-a-half years in jail and fined Rs 10 lakh by a special CBI court in a fodder scam case, related to the fraudulent withdrawal of Rs 89.27 lakh from the Deoghar treasury 21 years ago.