Last year saw political activist John Anthony Castro launch an aggressive campaign to keep former President Donald Trump off of this year's election ballot.

Castro's crusade against Trump was unsuccessful, and he now faces a legal battle of his own after getting arrested this week. 

Authorities say Castro filed 17 sets of fraudulent documents

According to The Hill, Castro was taken into custody on Tuesday, with the arrest coming days after he was hit with a 33-count federal indictment.

Prosecutors assert that Castro aided in the preparation of false tax returns and filed at least 17 sets of fraudulent documents with the IRS.

They allege that the virtual tax business he operated defrauded the government by providing clients with excessive tax refunds.

"Castro would promise a significantly higher refund than taxpayers could receive from other preparers and on many occasions, offered to split the additional refund with taxpayers," The Hill quoted prosecutors as saying in recently filed court documents.

Castro pledges that his case will go to trial

"In order to achieve these larger refunds, Castro generated false deductions, that were not based in fact, and which were submitted without the taxpayer’s knowledge," they added.

For his part, Castro provided a statement to The Hill in which he professed his innocence and claimed to have already paid the IRS $700,000 in 2021.

"I don’t care if they offered me one day probation and a slap on the wrist in exchange for a guilty plea," the anti-Trump activist was quoted as saying.

"This is going to trial. I am going to convince all 12 jurors that I am 100 percent innocent and that this is political retaliation," he insisted.

Castro's latest attempt to disqualify Trump fails

Castro's latest attempt at disqualifying Trump failed earlier this week after a Nevada judge ruled that his presidential campaign was simply ruse done to give him standing.

A federal judge in Nevada rejected former President Trump's 14th Amendment claim in Nevada that was brought forward by GOP presidential candidate John Anthony Castro. https://t.co/B9ZJcggbUG pic.twitter.com/TpM7CnxOg3

— The Hill (@thehill) January 10, 2024

"In rejecting his political competitor standing argument, courts have found that Castro improperly manufactured his standing merely to file this lawsuit," federal Judge Gloria Navarro wrote.

To support her finding, Navarro pointed to an interview Castro gave in which he admitted that he was not making a serious run for the White House before stressing that "the fight’s going to be in the courtroom."