A postmortem was being carried out last night on a young woman who died at her apartment in Galway city. Gardaí are treating the death as suspicious.
A young man was being questioned in relation to the death late yesterday.
The young woman, who was originally from Douglas, Cork, was due to be conferred as a doctor at NUI Galway next Tuesday.
Gardaí from Galway Garda station were called to the apartment, which is attached to Pat Hogan's pharmacy on Fr Griffin Avenue, at around 6.30am yesterday following an emergency call from a neighbour. There they discovered the body of the woman in her early 20s.
Supt Martin Lee of Galway said a man in his mid-20s who was known to the deceased was also found in the apartment with minor head injuries.
He was taken to University College Hospital, Galway, (UCHG) for treatment, and discharged yesterday morning.
The man was then arrested after his release from hospital and detained for questioning at Galway Garda station under Section 4 of the Criminal Justice Act.
He was still being questioned late yesterday.
Supt Lee said gardaí were not looking for anybody else in relation to the incident and the investigation was ongoing.
"We are doing house-to-house inquiries, and are asking neighbours or anybody who may have been in the vicinity of Fr Griffin Avenue during the course of the night or the early hours of the morning and who may have noticed or heard anything to contact Galway Garda station at 091-538000."
The scene was preserved for examination by the Garda Technical Bureau, and the State Pathologist Prof Marie Cassidy travelled to Galway yesterday afternoon to carry out a postmortem.
The dead woman's family travelled from Cork to Galway yesterday.
The woman was due to be conferred as a doctor at NUI Galway on Tuesday after six years of medical studies. She had an internship set up at UCHG starting on July 1st.
Pat Hogan's pharmacy was closed for business yesterday, and the premises was cordoned off with blue and white crime-scene tape.
A spokesperson for NUI Galway said they would not be commenting on the situation until all the information and facts were made public.
However, the woman was described by somebody who knew her at university as "a lovely, quiet little girl".
Senator Margaret Cox, who lives nearby on Fr Griffin Road, said the events of yesterday were "very worrying and very difficult for everybody involved".