The police said on Thursday that all four people found dead in a Goa city creek were murdered and they had arrested one suspect.
"One person has been arrested and we have detained some more people in this connection," Superintendent of Police Atmaram Deshpande told a press conference in Panaji.
Close examination of the bodies of the four deceased had revealed head injuries.
The admission takes the total number of people murdered in Goa between Oct 12 to 14 to eight, including five women and a four-year-old child.
Police officials said the two other unnatural deaths reported within the three-day period were suicides.
The dead included a 67-year-old man who has been identified as Baburao Solanke from Pune, a 35-year-old woman, a six-year-old boy and a four-year-old girl, the latter three still unidentified.
The bodies of all four were found floating in the Rua de Ourem creek, which runs through the heart of the city. Until Wednesday, the police had maintained that the four had in all likelihood committed suicide.
"The accused says the dead people used to collect scrap and stayed in a shed along the creek. The accused and his associates tried to rape the woman, which led to the murders," Deshpande said.
He said the accused had confessed to his crime. "We are in the process of tracking the others who were involved in the crime."
Deshpande could not throw light on the progress made in the investigations into the four other murders. In three cases, the killer had burnt the faces of the female victims in order to conceal their identity.
Crimes against women in Goa have hit the media spotlight in recent years. Recent murder victims have included British teenager Scarlett Keeling and the mysterious death of Russian teenager Elena Sukhonova.
Earlier this year, alleged serial killer Mahanand Naik, who has confessed to strangling 16 women with their own dupattas over 10 years, was arrested.