Flat No 326 in Noidas Sector-29,where the two Behl sisters locked themselves up,refuses to open its doors to the outside world. The government team investigating the case found themselves face-to-face with a dead end,quite literally,when the house key mysteriously disappeared on Friday. City magistrate Sanjay Chauhan told Newsline,I wanted to start with a proper tour of the house where the sisters had confined themselves. But unfortunately,we could not do that today since the key to the house could not be found. According to him,neighbours and RWA representatives had told the police that Sonali,the younger of the two sisters,had taken the keys with her when she was taken to Kailash Hospital. But,according to Sonalis brother Vipin,Sonali insists she never took the keys, Chauhan said. Eyewitnesses say that since they never saw Sonali lock the door,the neighbours may have taken the key. Usha Thakur,the social worker who called the police to rescue the two sisters,maintains that she never saw Sonali take it. Sonali just picked up a file and walked out of the house,into the ambulance. When police officers said the door should be locked,the neighbours asked a security guard to go upstairs and do it. The guard or one of the neighbours must have locked the door, said Thakur. Inspector Vijay Prakash of Sector-20 police station,Noida,one of the police personnel who participated in the rescue mission,said,Sonali never locked the door,she came out with us and never even looked back. So it has to be the RWA members or neighbours. However,Colonel Sharma,the RWA representative,said it was Sonali who took the key. The neighbours did not lock the house. Sonali took a dupatta and a file,and locked the house. At least thats what the security guard and neighbours told me. I was downstairs, he said,adding that as the door had an automatic lock,she could have locked it by just pulling it shut. Special Superintendent of Police S N Singh,however,said the mystery of the missing keys does not deserve a lot of speculation as the keys would probably not work anymore. During the rescue mission,we had to call a carpenter to break open the door. The lock is probably damaged, he said. Stating that the lock would probably have to be broken again for the magisterial inquiry,he said,Whenever the magistrate wants to go in,we will call the carpenter again. Meanwhile,doctors treating Sonali said her condition has started improving,although she is underweight due to prolonged starvation. She is conscious and is following verbal commands. Her urine output is also normal now,but we are still keeping her in the ICU for observation. Her body weight is less than 30 kg, said V B Joshi,Kailash Hospital spokesperson. He added that her sugar levels have increased,and though the blood pressure still hasnt stabilised,it is being maintained through medication. Statements of neighbours and social worker Usha Thakur were recorded on Friday,and the magistrate has summoned Vipin Behl for questioning.