All India Majlis-e-Ittehadul Muslimeen (AIMIM) worker Taufeeq Sheikh was arrested on Monday in connection with the murder of Bijyapur Congress leader Reshma Pednekar.
Pednekar was allegedly murdered last month and her body was found near Korti-Kolhar bridge in Bijapur on May 17.
Pednekar's husband had then lodged an FIR against the AIMIM leader following which a case of murder was registered.
A day before her murder, audio clips suggesting an illicit relationship between the deceased and AIMIM leader had gone viral on social media. Reshma had also filed a case against Sheikh in April for threatening her.
Prima facie evidence had shown that she was killed and her body was thrown into the river, police said.
Before joining Congress, Padekanura served as the Janta Dal (secular) district president of women's wing for over a decade. In 2013, she had contested and lost elections from Devarahipparagi assembly constituency on a JD(S) ticket.
On being denied a JD (S) ticket in the last assembly polls in the state, Reshma quit the party and joined Congress.