Four kidnappers, including two women, were detained for the abduction of Madhur, SP (Bhilwara) Nitindeep Bluggan said.
The kidnappers had forcibly taken away the child from a park where he was playing last evening.
"The kidnappers called Madhur's father Bhimrao Pinjare last night on his mobile and demanded Rs 50 lakh ransom. The call was traced to Chittorgarh following which the accused were held," he said.
Two of the kidnappers had to be hospitalised as they consumed some poisonous substance, the SP said.
"Mukesh (one of the kidnappers) is a private driver attached with the office of Public Works department in Chittorgarh where Bhimrao was earlier posted. He had hatched the conspiracy to kidnap the child to extract money," he said.
The women were being questioned to ascertain their role in the incident, the SP said.