Earlier in the day, the three-time Jama MLA had resigned from the party's primary membership and assembly membership.
Mrs. Soren sent her resignation letter to Assembly Speaker Rabindranath Mahato on Tuesday, while her resignation letter from primary membership was sent to party supremo Shibu Soren.
According to party sources, Sita Soren was upset with not being made a minister in the Champai Soren government.
Sita Soren is the wife of the late Durga Soren, son of JMM central president Shibu Soren.
"Ever since the demise of my late husband Durga Soren, who was a foremost warrior and great revolutionary of the Jharkhand movement, I and my family have been subjected to constant neglect.
We have been isolated by the party and family members, which has been very painful for me. I had hoped that things would improve with time, but unfortunately, that did not happen.
The JMM, which my late husband had built into a great party by virtue of his sacrifice, dedication, and leadership ability, is no longer a party today. I am deeply pained to see that the party has now fallen into the hands of those whose vision and objectives do not match our values and ideals.
"Despite the tireless efforts of Shibu Soren (Guruji Baba), who worked hard to keep us all united, alas, his efforts also failed. I am very saddened that I have taken the firm decision that I will have to leave the JMM and this family. Therefore, I am resigning from my primary membership in the party and request that you accept my resignation.
