Indian police say two men from the outskirts of New Delhi may have killed as many as 15 children and women.
Human remains were also found in the drain
On Saturday, police found 15 skulls near a house in the town of Noida after digging up the back garden and drains.
These discoveries followed earlier finds of large plastic bags filled with clothes, bangles and human remains.
The discovery has provoked the fury of many residents of a nearby slum, who said complaints about their missing children had been ignored by police.
Police said they began digging around the house on Friday after a domestic servant who worked there admitted that he had raped and killed several children.
The businessman who employed him has also been arrested, police say.
Both men appeared before a local court on Saturday, charged with rape, kidnapping and murder.
The children were reported to have been lured to the house with promises of sweets while the women were offered jobs.
Noida's police chief, RKS Rathore, said that so far 10 of the 15 victims had been identified by relatives.
The remains of the children were found hidden in bags
"The bodies recovered are those who are in our list," Mr Rathore said.
"They have been identified by their parents. They have identified the clothes."
Angered relatives, many of whom live in shanty housing bordering Noida, gathered at the house and some, anxious to find out if their child was among the dead, struggled with police officers.
"We told police that we suspected this man, but they repeatedly ignored out complaints," Kuldeep Kumar, whose four-year-old nephew has been missing since February, told the Associated Press news agency.
"We are poor people. We can't go to the police station every day."
Neighbours are reported to have contacted the police after smelling a foul stench coming from the drain outside the house.
The search for more remains continues. Local people say that almost 40 children have disappeared during recent months.