Four people have been arrested in the northwestern Indian state of Rajasthan in connection with the sale of a newborn baby boy for 40,000 rupees (about $722).

The child’s parents, Sandhya and Ashok Devi, and the couple they sold him to, Vinod and Shakuntala Agarwal, have been detained in the Sriganganagar district.

The baby’s mother, Sandhya, sold the child to her neighbor and his wife in order to acquire enough money to pay for medical treatments for their other child, a two-year-old.

"[Sandhya] had taken her paralytic son to a hospital in Udaipur where the doctors told her that his treatment would cost around 40,000 rupees," a local police officer told Indian media.

"Sandhya was pregnant at that time. When her neighbor, Vinod Agarwal, came to know that she was in need of money, he offered to bear the treatment cost of her paralytic son. In exchange, he demanded that she would have to sell her baby after delivery, in case it is a boy.”

Reportedly, Agarwal handed over half the sum to Sandhya just after she gave birth to the baby on July 31 and promised to pay the remainder when she physically gave him the child.

Police are also investigating six other people, including a government official, who may have been involved in this saga as middle-men in the transaction.

Baby-selling is a huge business in India.

Last week, Indian media reported on a large-scale baby market in which infants were taken from their (usually poor and desperate) birth parents and sold to childless, affluent coupes for as much as 500,000 rupees ($9,000). Such well-heeled couples often prefer buying newborns rather than endure the lengthy and frustrating process of legal adoptions.

One news report revealed that physicians and nurses at government-run hospitals in the state of Uttar Pradesh were openly selling newborn babies to the highest bidder.

“If anything of the sort is found, we will ask the district administration to help the families. I promise to ask the district administration to help in the investigations and contact the concerned families,” warned Uttar Pradesh Chief Minister Akhilesh Yadav.