US:The husband of John McCain's running mate, Sarah Palin, has refused to give evidence in the "Troopergate" investigation of his wife's alleged abuse of power as governor of Alaska.
Meanwhile, state senators claimed unco-operative witnesses were effectively sidetracking the probe until after US election day.
Todd Palin was among 13 people subpoenaed by the Alaska legislature.
McCain-Palin presidential campaign spokesman Ed O'Callaghan announced that Mr Palin would not appear because he no longer believed the legislature's investigation was legitimate.
Ms Palin initially welcomed the investigation of accusations that she sacked the state's public safety commissioner because he refused to fire her former brother-in-law, a state trooper.
However, she has increasingly opposed it since Republican presidential candidate John McCain picked her as his running mate. The McCain campaign dispatched a legal team to Alaska, including Mr O'Callaghan, a former top US terrorism prosecutor from New York, to assist Ms Palin's local lawyer.
Earlier this week, Alaska attorney general Talis Colberg said the governor, who was not subpoenaed, declined to participate in the investigation and said Palin administration employees who had been subpoenaed would not appear.
State senator Bill Wielechowski, a Democrat, said the McCain campaign was doing all it could to prevent the legislature completing a report on whether the Republican Party's vice-presidential nominee abused her power as governor.
Mr Wielechowski, a member of the panel that summoned the witnesses, said they could avoid testifying for months without penalty and that court action to force them to appear sooner was unlikely.
Ms Palin sacked Walt Monegan in July. It later emerged that Ms Palin, her husband and several high-level staffers had contacted Mr Monegan about state trooper Mike Wooten.
Ms Palin maintains she fired Mr Monegan over budget disagreements, not because he would not dismiss her former brother-in-law.
Mr Wooten had gone through a difficult divorce from Ms Palin's sister before Ms Palin became governor. While Mr Monegan said no one from the administration ever told him directly to sack Mr Wooten, he said their repeated contacts made it clear they wanted him gone.
Alaska senate president Lyda Green, a Republican foe of Ms Palin, said on Wednesday that the investigation was still on track. "The original purpose of the investigation was to bring out the truth. Nothing has changed," she said.
Without the testimony, the retired prosecutor hired to head the investigation could still release a report in October as scheduled, based on the evidence he has already gathered. - (AP)