A 16-year-old student of Ryan International School in Gurugram who wanted exams and a scheduled meeting between teachers and parents delayed is the prime accused in the murder of Class 2 student Pradhuman Thakur, the CBI said on Wednesday.CBI spokesperson Abhishek Dayal said the Class 11 student was detained on Tuesday night after "inspection of the crime spot, scrutiny of CCTV footage, call records, statements and questioning of several people" revealed that he had carried a knife inside the school campus on the day of the crime and used it to kill his junior school mate."The weapon used in the commission of crime is a knife which was recovered initially by police in Gurugram (Haryana). It is now with us," Dayal told reporters here.He said the detained student was weak in studies and "wanted to have examination and parent-teacher meeting postponed". Pradhuman, 7, was his random target.The parents of the detained student were kept informed throughout the investigation, said the spokesperson for the Central Bureau of Investigation.The CBI took over the case on September 22 from Haryana Police, nearly two weeks after the Class 2 boy was found with his throat slit in a school bathroom.The accused will now be produced before the Juvenile Justice Board, where the court is expected to decide whether he is to be treated as a major or a minor as per the Juvenile Justice (Care and Protection of Children) Act, 2015. he Haryana Police had earlier claimed that Pradhuman was killed by school bus conductor Ashok Kumar inside the toilset as the boy resisted a bid to sodomise him.While Ashok Kumar was arrested, Pradhuman's parents and two other staffers have claimed that he was being made a scapegoat.