The body of class II student Pradyuman Thakur, who was killed in the toilet of Gurgaon's Ryan International School last Friday, had no marks of sexual assault.
Dr Deepak Mathur who conducted the post-mortem of the 7-year-old's body said there were no signs of sexual assault.
The doctor said the child died due to excessive bleeding after he was attacked on his neck twice by bus conductor Ashok Kumar.
The accused had earlier admitted to the police that he killed Pradyuman using his knife after he resisted attempts of unnatural sex in the toilet.
Gurgaon police is convinced that besides Ashok no other person was involved in the gruesome murder.
"It is clear that only Ashok is involved," Gurgaon Police's ACP Birem Singh said.
"Questioning with bus conductor complete, remand has ended. He told us whatever we needed to know. We are satisfied," he said.
During questioning, two children disclosed that the accused bus conductor was present in the toilet before the incident.
The police will try its best to file chargesheet in the court by this Saturday.
ACP Singh said the act of negligence by the school is separate for which two people are being questioned.
Several lacunae related to installation of CCTV cameras at the school, lack of separate toilets for drivers and conductors, unsafe toilets, a broken boundary wall and lack of police verification of employees have already been found.
Two top officials of the school - Legal Head Francis Thomas and HR Head Jeyus Thomas - have been arrested by the Gurgaon police on charges of negligence.
A Special Investigation Team (SIT) of the Gurgaon police was probing the horrific murder which has sent shockwaves to parents across the country.