South Wales Police say they now believe the two bodies found in at an address in Merthyr Tydfil were a mother and young child.
Detectives are treating the deaths as unexplained and the bodies have not yet been formally identified, police added.
Troedyrhiw is a close-knit community in Merthyr Tydfil and local people are obviously shocked.
We have a team of officers at the scene and in the community looking for information that may assist our enquiries.
We would like to hear from anyone who has seen or heard anything suspicious or unusual in Church Street in recent weeks.
More top news
Merrill Lynch has been fined £34.5 million for failing to report 68.5 million transactions, the Financial Conduct Authority has said.
Most people back a change in the law to ban unpaid internships that last for more than four weeks, a new poll suggests.
The favourites to win the Venice marathon finished behind a local runner - after they were led along the wrong route by a motorcycle guide.