America's most widely-read newspaper today revealed painful details of a seven-month probe into its star war reporter that led to his resignation for lying to his editors.

The USA Today journalist Jack Kelley, who enjoyed a stellar career in which he hopped from war zone to war zone, came under suspicion after a fellow member of staff accused him in an anonymous letter of inventing reports.

The 43-year-old's fall from grace comes a year after The New York Times conducted an extraordinarily public post-mortem into reporter Jayson Blair, who was shown to have made up or plagiarised dozens of articles.

But Mr Kelley's case was different. USA Today asked him to quit despite failing to dig up proof that he had invented any of his stories, including one in which he described a suicide bomber just before he blew up an Israeli restaurant and another in which he accompanied nine Cubans trying to flee by boat.

The paper said they could not have confidence in any of his work after discovering that he had tried to fool their probe into one of his stories, a 1999 front-page story on Serbian war crimes in Kosovo.

The investigators telephoned his supposed translator in Serbia as a witness to prove that he had not invented the story. But when they analysed recordings of their conversations they discovered the translator was not who she claimed.

The investigation found Mr Kelley had allowed another woman to impersonate the witness and gave him two days to resign. Karen Jurgensen, USA Today Editor, accused her former employee of engaging in an "elaborate deception" during the investigation.

Mr Kelley, a finalist for a Pulitzer prize who had worked for the paper since 1982, maintains he is the victim of a witch hunt sparked by professional jealousy.

He said that he regrets having lied, but did so only in an attempt to clear his name. He claimed that he had panicked when he was unable to contact a translator who could have proved that his story was true, and allowed another translator to impersonate her.

His editors caught him out by calling the impersonator back and hiring private investigators to conduct expert voice analysis of the conversation that proved she was not the original translator.

A fellow reporter, Mark Memmott, was despatched to Belgrade in a vain attempt to track down the translator.

Mr Kelley was therefore unable to prove that he had seen a Yugoslav army notebook containing a direct order to "cleanse" a village of its ethnic Albanian residents during an encounter with a human rights activist.

An evangelical Christian who has said that he chose his profession "because God has called me to proclaim truth," Mr Kelley is now suspected by his former bosses of a more serious deception.

"Given Jack's actions, obviously it's hard to have confidence in his work," Brian Gallagher, executive editor, told The Washington Post.

USA Today also examined the journalist's telephone records and said they showed he had called Yugoslavia only once last summer, whereas he said he had made multiple attempts to contact the translator.

Mr Kelley said he had made the calls from other desks and outside the office because he did not trust his editors. His lawyer said that the newspaper hired private investigators who proved the deception and then confronted him.

The Post also quoted a former UN mission chief in Yugoslavia as saying that the existence of the notebook was "very probable".