Scotland Yard apologised today for "administrative errors" during investigations into the mysterious death of an MI6 spy found in a holdall.
The force said it was responsible for giving a coroner three names for the same witness ahead of the inquest into the death of Gareth Williams.
Elizabeth Guthrie is expected to be questioned about her contact with Mr Williams in the months before his death when the hearing gets under way later this month.
But Coroner Dr Fiona Wilcox told a pre-inquest review last week that "there has been some confusion" over her identity.
The Metropolitan Police Service moved to clarify the situation in a statement.
It said: "For the avoidance of doubt, the MPS would like to make it clear that Miss Guthrie has assisted the police investigation at every stage.
"Regarding the issue of the spelling of her name, the MPS would also like to clarify that this was not caused by Miss Guthrie but was a result of administrative errors when her statements were taken.
"Furthermore, at no point did Miss Guthrie ask the MPS to represent her views in this matter to the media.
"The MPS would like to apologise to Miss Guthrie, her family, and HM Coroner for any confusion that has been caused."
Miss Guthrie had been listed as Miss Gunther, Misa Guseiri and Elizabeth Guthrie in separate statements sent to Westminster Coroner's Court.
News of the error comes after the force also revealed a key line of its inquiries had been an 18-month DNA mix-up.
Forensic teams mistakenly flagged up a spot of DNA on Mr Williams's hand in 2010 - before realising just two weeks ago that it matched a scientist on the crime scene, the force told the review.
Family members of Mr Williams believe secret agents specialising in the "dark arts" hold the key to solving the death riddle.
Relatives believe a third party was either present when Gareth Williams died or broke into his home afterwards to destroy evidence, lawyer Anthony O'Toole last week's pre-inquest review.
Mr O'Toole said: "The impression of the family is that the unknown third party was a member of some agency specialising in the dark arts of the secret services - or evidence has been removed post-mortem by experts in the dark arts."
The inquest is due to begin on April 23.