WASHINGTON • A second intelligence official who was alarmed by US President Donald Trump's dealings with Ukraine is weighing whether to file his own formal whistle-blower complaint and testify to Congress, according to two people briefed on the matter.
The official has more direct information about the events than the first whistle-blower, whose complaint that Mr Trump was using his power to get Ukraine to investigate his political rivals touched off an impeachment inquiry.
The second official is among those interviewed by the intelligence community inspector-general to corroborate the allegations of the original whistle-blower, one of the people said.
The inspector-general, Mr Michael Atkinson, briefed lawmakers privately on Friday about how he substantiated the whistle-blower's account.
It was not clear whether he told lawmakers that the second official is considering filing a complaint.
A new complaint, particularly from someone closer to the events, would potentially add further credibility to the account of the first whistle-blower, a Central Intelligence Agency (CIA) officer who was detailed to the National Security Council at one point. He said that he relied on information from more than half a dozen US officials to compile his allegations about Mr Trump's campaign to solicit foreign election interference that could benefit him politically.
Other evidence has emerged to back the whistle-blower's claim.
A reconstructed transcript of a July call between Mr Trump and President Volodymyr Zelensky, released by the White House, also showed Mr Trump pressuring Ukraine. Mr Trump appeared to believe that its release would quell the push for impeachment, but it only emboldened House Democrats.
Because the second official has met with Mr Atkinson's office, it was unclear whether he needs to file a complaint to gain the legal protections offered to intelligence community whistle-blowers.
Witnesses who speak to an inspector-general are protected by federal law that outlaws reprisals against officials who cooperate with an inspector-general.
Whistle-blowers have created a new threat for Mr Trump. Though the White House has stonewalled Democrats in Congress investigating allegations raised in the special counsel's report, the President has little similar ability to stymie whistle-blowers from speaking to Congress.
The Trump administration had blocked Mr Atkinson from sharing the whistle-blower complaint with lawmakers but later relented.
Mr Trump and his allies have taken aim at the credibility of the original whistle-blower by noting that he had second-hand knowledge. The President has also singled out his sources, saying that they were "close to a spy".
Mr Atkinson has identified some indications of "arguable political bias" that the whistle-blower had in favour of a rival candidate.
But the inspector-general said that the existence of that bias did not alter his conclusion that the complaint was credible.
House Democrats have moved quickly in scrutinising Mr Trump's use of power to solicit potential foreign help in his 2020 re-election campaign.
Late last Thursday, they released explosive texts exchanged by State Department officials and Mr Trump's personal lawyer, Mr Rudy Giuliani, about pressuring the Ukrainians to commit to conducting the investigations that could help Mr Trump politically.
In one exchange, the Americans sought to have Mr Zelensky issue a statement promising to investigate a Ukrainian natural gas company where Mr Hunter Biden, the son of former vice-president Joe Biden, sat on the board.
The texts show a dispute about whether the President was trying to use a US$391 million (S$539 million) security aid or a White House meeting with Mr Zelensky as leverage - a charge at the heart of the impeachment inquiry.
Mr Trump has denied that he held up the aid as a quid pro quo.
Separately, he has ordered a substantial reduction in the staff of the National Security Council, according to five people familiar with the plans. Some of the people described the staff cuts as part of a White House effort to make its foreign policy arm leaner under new National Security Adviser Robert O'Brien.