An ‘Irish Heiress’ Conned Him. He Started a Podcast to Track Her Down.

She posed as a down-on-her-luck heiress who was battling with her Irish family over an exorbitant inheritance. Sympathizers lent her tens of thousands of dollars.

But Marianne Smyth, who was born in Maine, was not an Irish heiress, and there was no fortune. She has been accused over the years of using elaborate deceptions to swindle hefty sums of money in schemes that led to two felony convictions.

Now Ms. Smyth, 54, is facing more accusations, this time from the authorities in the United Kingdom, who are seeking her extradition from the United States. The charges, for fraud and theft, date from March 2008 to October 2010, when Ms. Smyth was living in Northern Ireland, according to a complaint filed in federal court in Maine. She was arrested last month in Maine, the U.S. Marshals Service said.

The arrest was “a miracle,” said Johnathan Walton, a Los Angeles-based reality television producer who has made it his personal mission to expose Ms. Smyth, after she was convicted of stealing more than $63,000 from him.

“This woman is a career conwoman,” Mr. Walton, whose credits include “Shark Tank” and “American Ninja Warrior,” said in an interview. “There are people who spend their lives masquerading as other people to trick you.”

A lawyer listed for Ms. Smyth in court documents did not immediately respond to emails and phone messages seeking comment.

Mr. Walton said he met Ms. Smyth in 2013 and they quickly became close friends. Dressed in designer clothes and generous with her money, she claimed she was from an established Irish family.

“She was always paying for things and buying my husband and me gifts,” he said. “Of course we believe that she’s this Irish heiress.”

They bonded, he said, over the pain of being disowned by their families. “She was like my sister,” he said.

Soon she came to Mr. Walton in distress, he said, claiming that her family had conspired to cut her out of an inheritance worth tens of millions of dollars, leaving her in need of cash. Mr. Walton lent her money, even letting her charge about $50,000 to his credit cards. He believed that she would pay him back.

Instead, Ms. Smyth used his money to settle the restitution she owed after being convicted of an earlier felony that involved the embezzling of funds from a travel agency, he said.

Mr. Walton reported Ms. Smyth to the police. A jury found her guilty in 2019 of stealing from Mr. Walton and she was given a five-year sentence. She was released early in December 2020, according to court documents.

Then, Mr. Walton, who had been blogging about his case and hearing from other accusers, took a step further in 2021 with “Queen of the Con,” a podcast about his friendship with Ms. Smyth and her trial.

His credit card debt, accruing interest each month, led him to file for bankruptcy and ruined his credit score. “I wanted to warn people about her,” he said. “I wanted to keep tabs on her. I wanted to find other victims.”

He said he has heard from people who have accused Ms. Smyth of assuming other false identities, including a child custody investigator, a psychic and a satanic priestess.

He began receiving tips, soon after the podcast’s release, that Ms. Smyth was living in Maine. “Listeners would tell me they saw her at the gas station or the supermarket,” he said.

Mr. Walton believes that the tips he passed on to a detective in Northern Ireland helped lead to Ms. Smyth’s arrest. The police in Northern Ireland have declined to comment on the case.

The accusations behind her arrest last month involve a period when Ms. Smyth was working as a mortgage adviser, according to a complaint filed by the U.S. attorney’s office for the district of Maine. One couple said they gave Ms. Smyth 20,000 pounds, or about $25,500, “to be invested in” a high-interest savings account with the Commonwealth Bank of Australia. But when they called the bank, the account did not appear to exist.

Another couple said that they gave her about £72,000, or $91,000, to purchase an investment property, according to the court document. Ms. Smyth furnished documents that appeared to detail the sale, and even sent them monthly payments from supposed tenants. But the sale never took place, they said, and Ms. Smyth was difficult to track down.

In all, Ms. Smyth abused her position to steal about £135,000, or $170,000, according to the complaint, which charges her with four counts of fraud and four counts of theft.

The accusations were first reported to the authorities in Northern Ireland in 2009, after Mr. Smyth had returned to the United States, and the authorities reviewing the case decided to pursue it once more in 2019.

An extradition hearing for Ms. Smyth, who remains in custody, has been set for April 17.

“The pen may be mightier than the sword, but the podcast is mightier still,” said Mr. Walton, whose podcast now has almost 11 million downloads. He said he wanted to encourage other people to come forward.

“Going public hurts the con artist,” he said. “That’s what you need to do.”