Four people have been arrested at a prison in South Wales after concerns about the conduct of staff.
South Wales Police confirmed the four had been arrested on suspicion of assault and misconduct in public office.
The force said in a statement that the arrests followed reports of a series of incidents at HMP Parc in Bridgend.
HMP Parc is operated by security company G4S, and is the only privately-operated prison in Wales.
The prison, which was opened in 1997, had a capacity of 1,652 in 2016.
Earlier this year, the government faced calls to take over the running of HMP Parc amid concerns over a spate of deaths.
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Detective Chief Inspector Dean Taylor said concerns were raised about the conduct of staff at the prison on Wednesday.
“Officers are at the early stages of the investigation and are working closely with G4S while inquiries are ongoing,” he added.
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The four people arrested as part of the investigation are a 23-year-old woman from Bridgend, a 45-year-old man from Pontcymer, a 25-year-old man from Merthyr, and a 35-year-old man from Llanelli.
Sky News has approached G4S for a statement.
