Jagan, as the young MP from Kadapa is popularly known, remained glued to the television set in his special cell since Friday morning to keep himself abreast of the vote count, informed sources said.
As it became clear that his party was heading for a sweep, his mother Vijayamma, wife Bharati, sister Sharmila and brother-in-law Anil Kumar drove to jail and congratulated Jagan.
The son of late chief minister Y.S. Rajasekhara Reddy is in jail for on charges of corruption. He was arrested by the CBI May 28 while campaigning.
After he was sent to jail, his mother and sister campaigned for the party, drawing huge crowds.
Meanwhile, there was mild tension outside the jail when his supporters celebrating the party's win gathered outside the jail.
e were heated arguments when police tried to disperse them. Party activists were raising slogans of 'Jai Jagan'.
In another development, the Enforcement Directorate (ED) filed a petition in the CBI court, seeking permission to question Jagan under the Prevention of Money Laundering Act.
Jagan is facing the allegations of routing investments into his companies through hawala and also of money laundering.
Image: YSR Congress supporters celebrate the party's victory in the by-elections in Hyderabad on Friday.