Story highlights Four people are being questioned in the case, the district police chief says

The bodies of three girls aged 6, 9 and 11 are found at the bottom of a well

Police say initial medical reports suggest the girls were sexually assaulted

The girls' mother says police should have acted more quickly

The mother of three girls who were found dead at the bottom of a well in western India after they were allegedly raped has called for those responsible to be caught and publicly hanged.

The bodies of the three girls -- aged 6, 9 and 11 -- were found in the well in Bhandara district in Maharashtra state on Saturday, police said.

They were reported missing two days earlier, said A.R. Tiwari, a local police inspector.

The shocking news comes as India is still reeling from the horrific case in New Delhi in which five men and a juvenile are accused of gang raping and murdering a 23-year-old woman in December. The five men are currently on trial.

Preliminary medical reports suggest the girls drowned, and that they had been sexually assaulted, Tiwari said.

JUST WATCHED India rape case drags on Replay More Videos ... MUST WATCH India rape case drags on 03:06

JUST WATCHED Report: India has failed its children Replay More Videos ... MUST WATCH Report: India has failed its children 01:41

JUST WATCHED 'Slumdog' star weighs in on gang rape Replay More Videos ... MUST WATCH 'Slumdog' star weighs in on gang rape 04:56

Four people are being questioned in connection with the assault, district police chief Arti Singh told CNN Thursday. No one has yet been arrested.

A local police officer in charge of the area where the incident took place has been suspended and replaced by Tiwari, she said.

In an interview with CNN affiliate IBN Thursday, the victims' mother said police didn't respond quickly enough to the girls' disappearance.

"Had the police searched for the girls in the neighboring areas, then they would have been found," said the woman, whose identity was withheld in accordance with Indian laws protecting the victims and families in sexual assault cases.

But police denied her allegations.

"We acted promptly," Tiwari said. "Wireless messages were issued the same day and police teams fanned out to find the girls."

The mother is nonetheless urging police to catch those responsible quickly.

"I appeal to the government to capture the culprits and hang them in public," she said.