The investigations into the Ryan school murder took a turn when the CBI absolved the conductor of murder charges and said that the crime was carried out by a class 11 student. The CBI is now looking at the possibility of more persons involved in the murder. While the murder was plotted and carried out by the child in conflict, the CBI is trying to ascertain if there were more people involved behind the cover up. The lead regarding the class 11 boy came in September itself, an officer part of the probe informed. We however did not want to jump the gun. We examined the footage over and over again and also sent it out for image enhancement and forensic analysis. The next step was to analyse the weapon used in the murder, the officer also informed. We kept a close watch on the child in conflict. We even paid a visit to his home and seized some material two months back. We did not want to reveal anything until we we had a fool proof case, the officer also informed. We were on the trail of the juvenile for at least a month. His behaviour was suspicious, but we did not act until we had a water-tight case, the officer also informed.