The CBI has summoned a warden of the Lucknow jail for interrogation on Wednesday,following disclosure by an undertrial that he had seen the warden taking away Dr Y S Sachan,former deputy CMO,from the jail hospital in the morning hours of June 22. After that Sachan was never seen in the jail and,in the night,he was found dead in an unlit toilet on the unused first floor. Officials did not reveal the identity of the man who gave this information,but said he was an undertrial,who was admitted to the jail hospital at that time. Officials added that they were treating warden Pahendra Singh as a suspect. The undertrial claimed to have seen Singh talking to Sachan around 7:45 am near his bed. After a short while,they walked out of the hospital,the undertrial told investigators. Earlier,during the judicial inquiry,two undertrials in the jail hospital had told Chief Judicial Magistrate Rajesh Upadhyay that someone had called Sachan from outside,saying that he had to go to court. Singh was on duty in the morning shift at the jail hospital on June 22. At 10:30 am,he reportedly shut the doors of the hospital,citing an inspection by Additional Chief Judicial Magistrate. The doors remained closed till 4 pm and no hospital inmates or prisoner was allowed to enter or exit,though no inspection took place. The CBI has found that Singh had gone to his room in the jail premises after 10:30 am and returned around noon for a few minutes to hand over charge to another warden,Ram Narain Tiwari. Sachan was lodged in the Lucknow district jail since April 4 in a case of alleged financial irregularities in the Family Welfare Department. On June 17,the police said he had planned the murder of CMO Dr B P Singh,which took place on April 2,and also had a link with the murder of Singhs predecessor Dr Vinod Arya on October 27 last year. After five days,Sachan was found dead. Though Sachans family said he had been murdered,the state government insisted that it was a suicide. However,the judicial inquiry that was conducted in compliance with the legal requirement held that Sachan had been murdered. On July 13,the day before the Lucknow bench of Allahabad High Court was to pass order on a petition seeking CBI inquiry,the government referred the matter to the CBI. The next day,the court ordered CBI investigation.