A grieving father believes a locked phone could hold crucial evidence which reveals his son's final moments.
James Cossey's body was discovered in a drainage ditch on Somerleyton Estate the morning after an illegal rave on May 20 last year.
An inquest ruled the 20-year-old former soldier, from Clover Road, Norwich, had drowned after taking cocaine and ketamine at the rave.
It was unable to determine exactly how Mr Cossey ended up in the water.
But as a post-mortem examination found no markings of defence which would signify third-party involvement, the death was not treated as suspicious.
When the soldier entered the water his mobile phone, a Samsung Galaxy 8, suffered severe water damage and police were unable to get it working again
However David Cossey, James' father, has since managed to reboot the phone.
He said: 'The police said they sent the phone off to technicians and they couldn't do anything with it.
'We left it in rice for six weeks and got it working.
'There will be photos to see or keep but there might be something to do with what happened on that night.
'I know he was found in the ditch, but how did he get there?
'I've struggled with it so much. It's horrible, it's the not knowing which is upsetting me.'
The 59-year-old is raising questions about Suffolk Police's attempt to recover the phone and the force's initial response to the rave.
Police were aware of the rave from around 1.15am but let it continue; his son's body was found eight hours later.
Mr Cossey added: 'It was an illegal rave, the police should have shut that down and my James would have been here today.'
In response to the queries a Suffolk Police spokesman said: 'The location of the gathering was a remote area of land that is difficult to access by vehicle and potentially would have put people at risk of falling in the river or dykes in the darkness – police need to consider ensure safety is a priority when dealing with such incidents.
'Regarding the phone, not having the pin code made it impossible for the police to unlock it.'
If you can help unlock the phone, model number SM-G950F, email james.carr@archant.co.uk
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