A mobile phone and two sim cards have been seized from cell of Shahbuddin, police sources said adding an another cell phone and a sim card was found from other prisoner.
Police has been conducting raids consecutively for the past two days in Siwan jail in view of by-election to Maharajganj constituency slated for tomorrow.
Shahbuddin, a former RJD MP and a known strongman of Siwan, has been in Siwan jail in various cases of kidnapping and murder registered against him in the past.
Voting for Maharajganj by-poll which is witnessing a triangular contest between JD(U) P K Shahi, RJD Prabhunath Singh and Congress Jitendra Swami will be held tomorrow.
Results would be declared on June 5.