Das had officially joined the outfit recently despite "several attempts by the police to kill her", the faction's spokesman Arunodoy Asom claimed in a statement e-mailed to media houses here.
"We welcome Das as a member of the outfit and hope an intellectual and patriot like her will help in the cause of our organisation," he said.
The police had earlier said that Das had joined ULFA and left for Nagaland on her way to Myanmar.
Das, who was a teacher of Assamese department as well as a warden of a hostel run by Purva Bharati Educational Trust in Jorhat, had come to her parents in Demow to attend a family function on February 6, spokesperson of Women in Governance Bondita Acharya had told reporters here on February 20.
Police had come to their house on February 8 to "hold some discussions" but she was not present at that moment and was directed to come to meet the SP in his office, Acharya had said.