THE investigation into the death of schoolboy Nathan Matthews has been condemned by his parents, who say they will still do not know what happened to their son almost three years after the tragedy.

Penny and Terry Matthews, from Water End, near Stokenchurch, have lodged complaints about the handling of the case by Thames Valley Police and the Crown Prosecution Service (CPS), which has left them without a conclusion 28 months after Nathan drowned during a swimming lesson at Thame Leisure Centre.

The Year Six Stokenchurch Primary School pupil's death on July 12, 2004, sparked an inquiry involving police, the CPS, South Oxfordshire District Council and the Health and Safety Executive. But Oxfordshire Coroner Nicholas Gardiner has never been in a position to hold an inquest as all the relevant information has not been presented to him.

Mrs Matthews said: "I still don't know what happened to Nathan. We have got no closure.

"This system makes losing someone ten times worse. It heightens the pain. It makes you frustrated and annoyed. It's like torture."

The family has written to the Independent Police Complaints Commission about the lack of progress in the case and Mrs Matthews believes the police should have been more thorough in their investigation at the time of the incident.

The complaint has now been passed back to the Thames Valley Police Professional Standards Department for internal investigation.

Mrs Matthews said: "I think it has been an appalling investigation.

"They should have done everything at the time. Now we are still waiting 28 months down the line."

Kate Smith, Thames Valley Police Oxford communications manager, said: "Nathan Matthews' mother has made a complaint to the Independent Police Complaints Commission. They have assessed the case and they are not going to investigate it.

"They feel it should be investigated internally.

"When we have finished the investigation we will write to Mrs Matthews. She then has the right to appeal against the findings if she wishes."

Mrs Matthews also wrote to the CPS to express her lack of confidence in her case worker after hearing no progress in more than a year.

Within days of the complaint Mrs Matthews received a letter back informing her that the CPS has decided not to prosecute anyone in relation to Nathan's death.

Mrs Matthews now feels the decision was rushed through after receiving her complaint, and has called for the CPS to reopen the case.

She said: "It is not the decision I am unhappy with. I know that nobody intended for Nathan to die.

"But they should at least do a detailed investigation. I think it is odd that after all this time I suddenly get a decision after I complain."

Lucy Littlewood, spokesman for the CPS, confirmed that a decision has been reached, but would not comment on the complaint.

She said: "If a complaint has been received it will be dealt with in the proper way."

Adrian Bidwell, head of operations at Soll Leisure Ltd, the company which runs Thame Leisure Centre, said it would be inappropriate to make any comment until an inquest had taken place.