Police are to examine the deaths of three people at a psychiatric hospital in Derbyshire where at least 65 patients are thought to have been abused.

Derbyshire Constabulary published a report last week alleging that scores of patients at the hospital were stripped naked, put in straitjackets, drugged and sexually assaulted between 1954 and the 1970s.

Most of the abuse is thought to have been committed by Dr Kenneth Milner, the hospital’s medical superintendent, who died in 1976. Police said he would have been questioned over rape and cruelty claims if he was still alive.

It is claimed that patients at the hospital were drugged with sodium amytal, which has sedative and hypnotic properties, before being questioned about potential past abuse.

The police report detailed one death at Aston Hall, that of 24-year-old Barry Wright, who drowned in the River Trent while trying to escape in 1959. His family were not told about his death and burial until a fortnight later.

The details of three other deaths – which were not previously brought to police attention – have now been published in the Times. James Holden, 25, John Wigley, 22, and Terence Comer, 19, all died in the River Trent in 1962.

A witness told press at the time that the three men “just walked forward – the water reached up to their chests, then up to their necks, and they continued walking until they disappeared”.

Barbara O’Hare, a former patient at the hospital who says she was abused, told the Times: “The police must look at all the deaths, I don’t see how they can’t now. There were no medical doctors at Aston Hall, no facilities to resuscitate. Were these people so drugged up they just wandered into the water?”

Aston Hall was founded in 1925 as a hospital for people with learning disabilities, and later became a treatment centre for children with learning disabilities and mental health issues. More than 50 local authorities sent children to Aston Hall, and lawyers believe there could be thousands of victims.

DCS Kem Mehmet said that since the publication of the report last week a further 27 victims had come forward. He said police had not spoken to the Wright family in compiling their report because there was so little information held by the coroner about his death.

Responding to the revelation of the deaths of the three men in 1962, he said: “The three would have been subject to a coronial investigation or inquest. The circumstances of the deaths would have been detailed by the coroner at that point and this information will be considered by officers as part of our investigation moving forward.

“As further information is received by our team, lines of inquiry will continue to be investigated in the same detailed and empathetic manner as they have been over the past three years.

“The Aston Hall investigation has been complex and has involved more than 130 people. With 27 new victims coming forward since the publication of the report, we will never rule out any new information and will investigate each piece of information thoroughly as has been done over the past three years.”