Shivashankar, a private employee, allegedly sexually assaulted the boy, who stays in his neighbourhood last night after luring him with a chocolate to his house, they said.
The boy's parents who heard him crying rushed to his rescue and lodged a complaint with the Jeedimetla police, who picked up Shivashankar today for interrogation, a senior police officer said.
The boy has been sent for medical examination, he said.
"The accused has been held on charges of sodomy. He is being interrogated," he said.