Chandana Chakraborty, head of the Bimala Sishu Griha center.

Indian police said Tuesday they have arrested the heads of an adoption center suspected of selling at least 17 children to foreign couples, the latest trafficking scandal to hit the country.

Investigators said children aged between 6 months and 14 years were sold to couples from Europe, America and Asia for between $12,000 and $23,000 and taken out of the country. Police in the eastern state of West Bengal arrested Chandana Chakraborty, head of the Bimala Sishu Griha center, and her deputy Sonali Mondal at the weekend after a tip-off from the federal adoption agency. “In the last two to three years, they have sold at least 17 children,” a police officer told AFP on condition of anonymity.

“We will try to contact the couples and are expecting more arrests in coming days.” One French couple paid 1.5 million rupees ($23,000) for a child in 2015, he said. The women were also involved in running two other homes in the area. “Two people were arrested after raids in three charitable homes on Saturday night,” Sashi Panja, state women and child development minister, said.

Investigators said they had been monitoring the charity since June when child welfare authorities found discrepancies in their records and relocated all the children from one of the homes.

One said the accused ran health camps to identify poor and unmarried pregnant women and convinced them to give away their babies for adoption after paying them.

“They used fake fitness certificates and police stamps to process the adoption applications,” the officer said.

India has an estimated 30 million orphans, but the rules governing international adoptions are strict and domestic adoptions remain relatively rare.

Only 3,011 children were legally adopted by local couples in India between April 2015 and March 2016, down from 3,988 in the previous period, according to the Central Adoption Resource Authority.

Experts say desperate couples wanting to adopt in India are often frustrated by lengthy bureaucratic delays and complex rules, pushing them toward the thriving illegal adoption market.

In recent years the federal government has pledged to relax the adoption rules for local couples.

For foreigners and couples of Indian origin living abroad, the number of adoptions has risen by almost half but they remain subject to intense scrutiny, and the adoption process can take years.

The latest scandal comes four months after police arrested 18 people over the sale of newborn babies in the same state.

The gang stole babies from nursing homes, smuggling them out in biscuit boxes and keeping them at adoption centers before selling them.

The scale of the operation is still being uncovered, and the remains of five newborn girls were recovered from one of the homes in November.