THE case of a Derry mother killed by British troops in 1971 has taken a bizarre new twist with news that a police file promised to her family earlier this year cannot be found.

Mother-of-six, Kathleen Thompson (47) was shot dead while standing in her back garden on November 6 1971.

Shot by a member of the Royal Green Jackets, she died as a result of a single bullet wound to the chest.

Mrs Thompson’s family always maintained no proper investigation of their mother’s death was ever carried out by the RUC at the time.

The only statements available are those presented by soldiers at Mrs Thomp-son’s inquest.

Following a long campaign, police told the Thompson family that no investigation file concerning their mother’s death could be found.

But in a dramatic twist earlier this year, the family was informed a police file had turned up.

The news was delivered just hours before Ulster Television broadcast an Insight programme about the case.

The programme subsequently reported the police statement that a file had been found.

Mrs Thompson’s family asked to see the file and in a series of letters was told they would be shown the investigation file in the presence of a senior officer.

But despite further letters between their legal team Madden and Finucane and the police, the file never materialised.

Last month, Deputy First Minister Mark Durkan also took up the matter.

Now the case has taken on another twist. Last Friday, the Thompson family received a letter from NIO minister, Des Browne.

In his letter – which followed a meeting with the family in October last year – Mr Browne said his office had been in contact with a range of agencies, including the police.

The minister said: “The PSNI inform us that they are unable to locate the file relating to your mother’s case.”

The news brought an emotional reaction from Mrs Thompson’s daughter, Minty who said that after 31 years her mother’s memory was still being insulted.

Describing the latest development as “diabolical,” Ms Thompson said it looked as if the police were using Mr Browne to say there was no file.

She said her family now wondered if a file ever existed or if it contained something which the police did not want her family to see.

Ms Thompson said her mother failed to achieve justice at the time of her death and now, almost 31 years on, she was still being denied justice.

Last night a police spokesman said: “We intend to discuss this matter with the Northern Ireland Office and will respond in due course.”