Republican poll monitors in Michigan on Tuesday bolstered President Trump’s claims of widespread election fraud, telling a state Senate committee that they witnessed mysterious truckloads of absentee ballots delivered to a counting center in Detroit and Democratic workers scanning the same ballots multiple times in tabulation machines.
Also on Tuesday, several election whistleblowers, including a contract driver for the U.S. Postal Service, said at a press conference near Washington that hundreds of thousands of mail-in ballots disappeared or were backdated and that pro-Trump mail was undelivered in Pennsylvania, Wisconsin and Michigan.
But even as the witnesses told riveting tales of an election rigged for Democrats, Attorney General William P. Barr was undercutting the president’s case. Mr. Barr said the Justice Department hasn’t seen evidence of widespread voter fraud that would overturn the presidential election victory of Joseph R. Biden.
“To date, we have not seen fraud on a scale that could have affected a different outcome in the election,” Mr. Barr told The Associated Press. “There’s a growing tendency to use the criminal justice system as sort of a default fix-all, and [when] people don’t like something they want the Department of Justice to come in and ‘investigate.’ “
Trump attorneys Rudolph W. Giuliani and Jenna Ellis, who are urging Republican-controlled legislatures in Pennsylvania, Arizona and other states to overturn Mr. Biden’s win because of fraud, disputed Mr. Barr’s conclusion.
“With the greatest respect to the attorney general, his opinion appears to be without any knowledge or investigation of the substantial irregularities and evidence of systemic fraud,” they said in a statement.
“There hasn’t been any semblance of a Department of Justice investigation. We have gathered ample evidence of illegal voting in at least six states, which they have not examined.”
Mr. Barr visited the White House on Tuesday for what was described as a previously scheduled meeting. The attorney general also announced that he had appointed U.S. Attorney John Durham as special counsel on Oct. 19, two weeks before Election Day, to continue investigating suspected misconduct by Obama administration intelligence officials involved in spying on the Trump campaign in 2016.
Although the president is intensely interested in that probe, he is more urgently trying to prove that massive voter fraud cost him the election. He was paying close attention to the Michigan hearing at the same time the attorney general was minimizing those claims.
“We won Michigan by a lot!” Mr. Trump tweeted during the hearing in Lansing.
The president’s attorneys said they have “many witnesses swearing under oath they saw crimes being committed in connection with voter fraud.” One of them is Mellissa Carone, an information technology worker contracted to work for Dominion Voting Systems in Michigan on Election Day.
Ms. Carone told the Republican-led state Senate Oversight Committee that she witnessed election workers at a convention center in Detroit scanning mail-in ballots multiple times whenever the tabulation machines rejected them.
“What I witnessed at the TCF Center was complete fraud,” she said. “At least 90% of those workers were all in on this. They were re-scanning, counting ballots eight to 10 times.”
She said she didn’t see a single vote for Mr. Trump during the 27 hours she spent at the ballot-counting center, and she described a “big data loss” in the voting system on the afternoon of Election Day.
State Sen. Michael MacDonald, a Republican, called the testimony of Ms. Carone, who has spoken with the FBI, “incredibly compelling.” Some in the audience applauded Ms. Carone’s appearance, while a group of “Stop the Steal” demonstrators outside watched the hearing through windows.
The committee heard testimony from other witnesses who described similar concerns about the chain of custody of Michigan’s mail-in ballots, lack of access for Republican poll watchers and the voting system’s vulnerability to hacking.
At least two witnesses said they saw a truck delivering large batches of mail-in ballots to the counting center around 4 a.m. on the morning after Election Day, and they couldn’t get an explanation where the ballots came from.
Former state Sen. Patrick Colbeck, a Republican poll challenger, urged the legislators to take control of the selection of presidential electors.
“There are options before you,” Mr. Colbeck told his former colleagues.
It’s not clear what, if anything, legislators will do with the testimony. The state has certified its election results showing that Mr. Biden won Michigan by 154,188 votes. The deadline for resolving election disputes is Dec. 8. Electors meet in each state on Dec. 14 to cast their ballots.
A Wayne County circuit court judge ruled three weeks ago that testimony by Ms. Carone and others who said they witnessed voter fraud in Detroit was “not credible.” Mr. Giuliani is expected to appear before a Michigan state House committee on Wednesday.
Mr. Colbeck called on Michigan’s legislators to conduct a complete review of the election in every county. The state canvassing board has rejected calls for a statewide audit and has certified the election results.
“I believe you need a full forensic audit,” Mr. Colbeck said. “They haven’t demonstrated chain of custody on any of the key election data.”
State Sen. Jeff Irwin, a Democrat, disagreed.
“I think it’s probably telling that the Trump campaign did not request a recount in Michigan,” he said. “It seems pretty clear to me that they know that a recount would mess up their current strategy, which is just to throw up a bunch of smoke and mirrors. We need some evidence, we need some proof. All we’ve got here is conjecture and musings by former Sen. Colbeck.”
Pro-Trump lawyer Sidney Powell filed a lawsuit last week against Michigan officials claiming widespread election fraud. That case is pending.
In Arlington, Virginia, several whistleblowers raised fresh questions Tuesday about possible election fraud. They said up to 288,000 ballots disappeared, another 100,000 ballots were improperly backdated, and mail promoting the president was trashed while mail for Mr. Biden was delivered.
Postal subcontractor and truck driver Jesse Morgan said he transported 144,000 to 288,000 completed mail-in ballots on Oct. 21 from Bethpage, New York, to a depot in Lancaster, Pennsylvania, where his trailer containing the ballots disappeared.
“As things became weirder, I got to thinking and wondered why I was driving complete ballots from New York to Pennsylvania,” Mr. Morgan said. “I didn’t know why, so I decided to speak up.”
Other witnesses said Trump campaign mail in Traverse City, Michigan, was put into bins labeled “undeliverable bulk business mail” while the same kind of mail for Mr. Biden was delivered on time.
The claims were revealed by the Amistad Project of the Thomas More Society, which is conducting its own investigation of election fraud.
“The whistleblower accounts released today, detail the failure of election officials in blue jurisdictions to maintain ballot chain of custody, allowing for the potential infusion of fraudulent ballots,” the group said. “The accounts also reveal multi-state illegal efforts by USPS workers to influence the election in at least three of six swing states. Details include potentially hundreds of thousands of completed absentee ballots being transported across three state lines, and a trailer filled with ballots disappearing in Pennsylvania.”
In Wisconsin, the Trump campaign on Tuesday filed a lawsuit to the state Supreme Court challenging Mr. Biden’s win there and citing “fraud and abuse” at the polls. Mr. Trump’s attorneys said the recount of the ballots in Wisconsin uncovered “fraud and abuse that irrefutably altered the outcome of this election.”
The recount, conducted at the request of the Trump campaign, was completed Sunday and showed Mr. Biden on top by 20,700 votes. The state certified the results Monday.
The Trump campaign’s lawsuit said four cases of unlawful conduct in the election affected an estimated 221,000 ballots — enough to change the outcome.
“We know with absolute certainty illegal ballots have unduly influenced the state’s election results. Wisconsin cannot allow the over 3 million legal ballots to be eroded by even a single illegal ballot,” said Trump campaign attorney Jim Troupis. “We will continue fighting on behalf of the American people to defend their right to a free and fair election by helping to restore integrity and transparency in our elections.”
• S.A. Miller contributed to this report.