The Haryana Police is scrutinizing the records of Ryan International group and has enough evidence to investigate the case, said a top police officer.
Sandeep Khirwar, Gurugram Commissioner of Police, said "Chargesheet will be filed within a short time in connection with the gruesome murder of 7-year-old boy Pradyuman Thakur.
Meanwhile, questioning of the teaching staff is underway at the school premises.
Earlier, the Gurgaon Police detained the Ryan International School's gardener, Harpal Singh. The cops are likely to arrest some more persons in connection with the case, a senior SIT officer said.
Besides Harpal Singh, the SIT has questioned 17 persons including section inchage-Anju Dudeja, suspended acting principal-Neerja Batra, former principal Rakhi Verma, bus driver Saurabh Raghav, bus contractor Harkesh Pradhan and eight security guards.
SIT teams on Wednesday searched the school for clues to the crime while a CBSE panel also inspected the premises to examine loopholes in security arrangements.
(With agency inputs)