Bharat's body was found in a sack by passers-by on Monday evening. According to police, he had been strangled to death.
Police arrested tutor Bittu, 19, on suspicion of murdering the minor, Bhopal Deputy Inspector General of Police Santosh Singh told IANS.
When Bharat, a student of Christ Memorial School, did not return home after school on Monday, his six-year-old sister Kanak, who studies in the same school, told her parents that her brother was seen with "Bittu uncle".
The murdered boy's mother told reporters that Bittu had threatened to harm her son if she did not "go to him" (Bittu).
In a CCTV footage, a man resembling Bittu is seen carrying a sack on his motorcycle, police said.