HMP Parc in Bridgend, South Wales, which opened 1997, was previously praised as safe and well-run, and was described in largely positive terms during its last inspection in 2022.
Officers were called just after 9.15pm on Friday following reports of concern for the welfare of two people in Bryn Terrace, Cefn Cribwr, near Bridgend.
The messages allegedly show staff members at HMP Parc in Bridgend, south Wales, mocking one inmate who had self harmed as 'daft' and boasting of 'punching the f*** into' another.
WARNING GRAPHIC CONTENT: Sara Platt (inset), from Bridgend, South Wales, was left in so much pain she 'wanted to die', after Turkish surgeon attempted to perform a loose skin removal