A Jharkhand court Monday extended till June 28 former union minister Yashwant Sinha's judicial custody after the Bharatiya Janata Party leader refused to seek bail.Sinha was arrested June 2 for leading a demonstration at the state Electricity Board office in Hazaribagh town and was sent to 14 days' judicial custody next day after he refused to furnish the bail bond. BJP sources said senior party leader L.K. Advani might meet Sinha in jail Tuesday.Meanwhile, the BJP Monday started phase-wise agitation against the prevailing power crisis in the state.