Alaska Governor Sarah Palin [Images], the running mate of John McCain [Images], 'abused her power' in seeking to get her former brother-in-law fired as a state trooper, an ethics report has found, dealing a blow to the Republican presidential nominee who is struggling to hold ground against Democrat rival Barack Obama [Images].

Coverage: US Presidential Elections '08

44-year-old Palin 'knowingly permitted a situation to continue where impermissible pressure was placed on several subordinates in order to advance a personal agenda: To get Trooper Michael Wooten fired,' the 263-page state legislative investigative report said on Friday night.

The investigation looked into Palin's sacking of Public Safety Commissioner Walter Monegan, who claimed that he was dismissed because he refused to bow to pressure to fire Wooten, who was involved in a bitter divorce and custody battle with the Governor's sister. Palin insists the firing was over a budget dispute.

The legislative panel, which authorised the investigation, released the report, but did not immediately vote whether to endorse its findings, The Boston Globe reported.

However, the report, which found that Palin violated the state's ethics law banning public officials from using their offices for personal gain, did not say whether Palin should be censured by the Legislature or whether the matter should be referred for criminal investigation, the paper reported.

As the November 4 presidential race narrows, the report thrusts a new issue into the campaign when Palin's reputation as a reform-minded candidate is already being subjected to scrutiny. The Republicans may also face Democrats' attacks on the matter.

The report's findings were revealed as Obama scored a double-digit 11-point lead over McCain for the first time in a Newsweek poll amid deep concerns about economy.

In the latest poll, Obama leads McCain by 52 per cent to 41 per cent among registered voters compared to a Newsweek survey carried out a month ago, which had the two tied at 46 per cent.

The investigation into the 'Troopergate' case also found that Palin 'knowingly' let her husband, Todd, use the resources of the Governor's office 'to find some way to get Trooper Wooten fired'.

Much to the displeasure of the probe panel, Palin had refused to testify before it.

While Palin could fire Monegan 'for almost any reason, or no reason at all', it was 'impermissible' to put pressure on him to dismiss Wooten, the report concluded, according to the paper.

Palin and Republican presidential candidate John McCain have denied that she acted improperly in the firing of Monegan.

The report 'shows that the Governor acted within her proper and lawful authority in the reassignment of Walt Monegan', a campaign statement was quoted by the paper as saying.

The findings come at a time when Palin, the mother of five, is criticised by some in the political circle for her lack of experience and her halting answers in recent television interviews.

Fighting back such attacks, the McCain campaign said she was a uniquely qualified outsider who can help reform Washington.

The legislative inquiry into the 'Troopergate' matter was approved by a bipartisan vote, but the McCain campaign alleged that it was a partisan 'witch hunt', the paper said.