Police will not pursue further prosecutions over treatment of an elderly patient at two hospitals.
The family of Lilian Williams, from Porthcawl, complained of neglect to South Wales Police in September 2013.
She was admitted to Princess of Wales Hospital, Bridgend, and Neath Port Talbot Hospital between 2010 and 2012.
Three nurses have already pleaded guilty to wilful neglect of patients. Another two are due to go on trial later this year
The force has met with Mrs Williams' family to discuss the decision, following their investigation.
Mrs Williams' son Gareth said: "Since my mother's case was first publicised by the BBC, we are aware of several dozen other families who have contacted us expressing serious current ongoing concerns about the hospital.
"We implore them to do as we did and report them to South Wales Police. The number of seriously alarming cases that are still being reported to us on an almost daily basis is disturbing."
Det Ch Insp Mark Lewis said: "A separate investigation specifically investigating the monitoring of blood sugar levels by nurses within Abertawe Bro Morgannwg University has previously led to three nurses pleading guilty to the wilful neglect of patients, one of whom was Lilian Williams."
In a statement, Abertawe Bro Morgannwg University Health Board said it is hoped it would end "rumours and speculation".
A spokesman added: "Notwithstanding the outcome of the police investigation we accept that there were significant shortcomings in Mrs Williams' care, which we very much regret and for which we have apologised to Mr Williams."