Tony Gauci, the Crown's key witness, expressed an interest in being rewarded nine years prior to giving evidence against Abdelbaset Ali Mohmed al Megrahi, the Libyan convicted of the bombing, according to the documents.
They have been released by John Ashton, author of Scotland's Shame: Why Lockerbie Matters.
The Crown Office last night said no witness was offered any inducement by the Crown or the Scottish police before or during the trial.
Last year, the 800-page report of the Scottish Criminal Cases Review Commission was published, but many of the accompanying documents have never been seen. Those released yesterday reveal that the FBI told the police that "unlimited money" was on offer for the witness. They indicate police believed paying Gauci and his brother Paul would ensure they would not embarrass the police or Crown.
A letter from a senior Scottish officer on the case, dated 1991, states Tony Gauci was interested in reward money and that "if a monetary offer was made to Gauci this may well change his view and allow him to consider a witness protection programme".
After Megrahi's conviction, the senior investigating officer lobbied the US Department of Justice to increase the previously discussed rewards of $2 million for Tony and $1m for Paul.
According to the intelligence report, the Crown Office was aware of the reward application after the first appeal, but did not become involved.
A Crown Office spokesman said: "No witness was offered any inducement by the Crown or the Scottish police before and during the trial and there is no evidence that any other law enforcement agency offered such an inducement. These documents relate to an issue which was before the Appeal Court in Megrahi's second appeal against conviction."
He added the Crown had been preparing to defend Megrahi's conviction when he abandoned the appeal.