A new court filing has cast further doubt on the accuracy of a list of “likely non-citizen” voters that the administration of United States President Donald Trump sent to the state of California ahead of the midterm elections.

On Saturday, the Coalition for Humane Immigrant Rights (CHIRLA), an advocacy group, submitted an analysis to the court conducted by two data scientists from the University of California, Los Angeles (UCLA).

It found that more than four in every 10 names on the list were not on California’s voter rolls.

It also found that thousands of potentially eligible US citizens were incorrectly identified as ineligible to vote.

The Trump administration’s list, delivered to California in early October, had suggested that as many as 20,930 “likely non-citizens” were registered on the state’s voter rolls.

That list has formed the basis of a lawsuit, filed on October 15, that calls on California to sequester any ballots sent to those “likely non-citizens”, preventing them from being tallied as part of voting results.

The lawsuit is unfolding in the final days before Tuesday’s pivotal midterm elections, which will decide which party controls the US Congress, as well as key state and local offices.

Trump has expressed fear that, if his Republican Party loses its majorities in the two chambers of Congress, he could be impeached.

The Republican leader also has a track record of spreading false information about elections, including that his defeat in the 2020 presidential race was the result of a “rigged” vote.

He has often targeted California in his criticism. The state – the most populous in the country – is considered a longtime left-wing stronghold. It will elect 52 seats to the 435-member House of Representatives in Tuesday’s elections.

Already, Trump has accused California of “cheating” in its June 2 primary elections, after several Republican candidates underperformed, including Los Angeles mayoral hopeful Spencer Pratt.

Under the US Constitution’s Elections Clause, election administration falls solely to the states, though Congress may pass regulations governing voting.

Critics, including California’s Democratic Governor Gavin Newsom, have cited that fact in their rebuttal to Trump’s lawsuit.

All 50 states already prohibit non-citizen voting in federal elections and undertake measures to prevent voter fraud, which is considered exceedingly rare.

Other states that have received similar lists of “likely non-citizen” voters have also found significant errors in the Trump administration’s accounting. Nevada, for example, found that none of the names included on that list were non-citizen voters.

Such errors have raised concerns that eligible citizens would see their votes denied if the Trump administration wins its California lawsuit.

Still, the Trump administration has threatened state officials with prosecution over the potential for non-citizen voting.

It has also vigorously pursued its lawsuit through federal court. On Friday, the 9th Circuit Court of Appeals in San Francisco rejected the complaint a second time, determining it unconstitutional.

“We decline the United States’s invitation to contravene the Elections Clause by undermining the Constitution’s plain text,” the court majority wrote in its ruling.

In Saturday’s court filing, the data scientists from UCLA’s Voting Rights Project found that 8,880 names on the list were not listed anywhere in California’s current voter files, a proportion of 42 percent.

Many other names on the list were either confirmed as US citizens or may correspond to US citizens.

“This review proves, at least as a preponderance of the evidence, that demands of election officials under criminal and civil threats, endangers the voting rights of plaintiff CHIRLA’s members and clients,” the filing said.

It was co-signed by the Democratic candidate to succeed Newsom as governor, Xavier Becerra.