President Trump's personal lawyer Rudy Giuliani told Reuters Monday he was paid $500,000 in consultancy work for the fraud prevention firm Fraud Guarantee, co-founded by indicted Ukrainian-American businessman Lev Parnas.

Why it matters: Parnas and Igor Fruman were arrested this month and charged with violating campaign finance laws and conspiracy. The Trump donors had helped connect Giuliani with Ukrainian officials as part of his efforts to investigate former Vice President Joe Biden and his son.

The New York Times reported last week that New York federal prosecutors had launched a criminal investigation to determine whether Giuliani "broke lobbying laws in his dealings in Ukraine."

The federal prosecutors are looking into Giuliani's personal business relationships with Ukraine, the Wall Street Journal reported earlier Monday.

What they're saying: Giuliani told Reuters Parnas' company, Fraud Guarantee, "engaged Giuliani Partners, a management and security consulting firm, around August 2018."

"Giuliani said he was hired to consult on Fraud Guarantee’s technologies and provide legal advice on regulatory issues," Reuters reports.

"Giuliani told Reuters the money came in two payments made within weeks of each other. He said he could not recall the dates of the payments. He said most of the work he did for Fraud Guarantee was completed in 2018 but that he had been doing follow-up for over a year."

The big picture: Fraud Guarantee is based in Boca Raton, Florida. The company's website states its mission is to "help reduce the risk of fraud as well as mitigate the damage caused by fraudulent acts."

Go deeper: Foreign-born Giuliani associates arrested on campaign finance charges

Editor's note: This article has been updated with more details on Fraud Guarantee.