British police opened an investigation on Tuesday into a hospital where hundreds of patients are believed to have died prematurely after being given powerful painkillers.
Police are examining the care provided to patients who died at Gosport War Memorial Hospital in southern England between 1987 and 2001, police said in a statement.
A review last year found that more than 450 people had their lives shortened at the hospital while another 200 were "probably" also given strong opioids.
"This is a highly complex and emotive case that some family members have been living with for more than 30 years," said Nick Downing, the police officer who has been reviewing the findings of the review.
"I hope the news that we will now be carrying out a full investigation is of some comfort to them," he said.
Maggie Cheetham told the BBC she wanted "closure" for her aunt Ethel Thurston who died in 1999 aged 78 after being admitted to the hospital following a fall.
"All she needed was some tender loving care. She did not deserve to die," Cheetham was quoted as saying.
"I want to know why she was given the cocktail of drugs, and I want someone held to account for killing her."
Last year's review found there was an "institutionalised regime" at the hospital of prescribing and administering amounts of opiate medication that were not clinically justified.