A woman who died after an incident in Mountain Ash on Tuesday has been identified as 20-year-old Bethan Louise Callaghan.
Paramedics were called to an address in Pentwyn Avenue that afternoon and Ms Callaghan was taken to hospital, where she later died.
Officers are still investigating the circumstances surrounding her death.
A 36-year-old man arrested on suspicion of her murder is still being questioned.
Det Ch Insp Dorian Lloyd said: "We are continuing to appeal to anyone who has any information in relation to this incident.
"We would particularly like to hear from anyone who witnessed, or has information about, a disturbance that may have occurred in Pentwyn Avenue, or the lane at the rear of Pentwyn Avenue, in the early hours of the Tuesday morning, shortly after midnight or thereabouts."
Anyone with information is asked to call Merthyr Police Station on 01685 724 272 or Crimestoppers anonymously on 0800 555 111.