Police investigating the unresolved deaths of four soldiers at Deepcut barracks failed to follow up potential suspects who could have been responsible for their murder, according to a new report into the deaths.
The soldiers died in mysterious circumstances at the Surrey army base between 1995 and 2002 amid reports of systematic bullying from senior officers.
Devon and Cornwall police reviewed Surrey police's investigation and found that the force failed to follow up specific individuals who could have killed the soldiers, according to the report seen by the BBC.
The 140-page document said it was impossible to say whether or not the individuals should have been considered suspects or eliminated from inquiries.
But the review said that Surrey police failed to investigate a potential suspect known as the "unknown white male" who could have been connected to the death of Private Cheryl James, an 18-year-old who was found dead with a single bullet wound to the head at Deepcut in 1995.
"The unknown male should have been subject to a Trace and Interview action," said the report.
"Operation Stanza [the review] believes insufficient investigative work took place to identify this unknown male who could have potentially been a suspect."
The BBC also quotes the Devon and Cornwall review as finding evidence of a "possible mindset" held by individuals leading the original inquiries who thought that the re-investigations were in some way "different".
James's father, Des James, has now called for a public inquiry, criticising Surrey police for investigating a suicide rather than considering all alternatives.
"[The report] simply confirms what we have always believed – that this was a hurried investigation, put together quickly, more to placate public opinion and media attention than to realistically and honestly find out what happened to these young people," said James.
Surrey police denied failures to follow up potential leads. In a statement, representatives told the BBC that the force had had "an open-minded approach" and "considered all hypotheses with equal weight".
Surrey police also pointed out that Devon and Cornwall produced no evidence to say that they missed anything by not following up the suggested leads.
The other soldiers who died from gunshot wounds at Deepcut were Private Sean Benton, 20, from Hastings, East Sussex, Private Geoff Gray, 17, of Hackney, east London, and Private James Collinson, 17, of Perth, Scotland.
A coroner recorded a verdict of suicide for Benton but the inquests into the other three returned open verdicts.
A report by Nicholas Blake QC in 2006 found that bullying and "foul abuse" were a routine part of life at the army's training barracks at Deepcut, although no evidence of deaths being anything other than self-inflicted was found.