Ahmedabad, Sep 26 : Karnataka High Court's most senior judge Jayant Patel, who had ordered a CBI investigation in the controversial fake Ishrat Jahan encounter case in Gujarat, on Monday resigned reportedly for not being elevated as Chief Justice. Patel, the senior-most puisne judge of the Karnataka High Court after the chief justice, sent his resignation letter to Chief Justice SK Mukherjee. It is believed Justice Patel, who was Acting Chief Justice of the Gujarat High Court before being posted to Bengaluru, resigned in a huff over his transfer to the Allahabad High Court, where he would be the third most senior judge. In fact, the Gujarat High Court Bar Association had even raised the non-appointment of Justice Patel with the Collegium and called it shocking. This was when he was transferred as a judge in the Karnataka High Court after being an Acting Chief Justice. Justice Patel had not only ordered a CBI investigation in the controversial fake encounter case of Ishrat Jahan but had also monitored the probe, which included looking into the role of officials of Intelligence Bureau. He was sworn in as a judge of Karnataka High Court on February 13 last year, while he was appointed the Acting Chief Justice of the Gujarat High Court on August 13, 2015.