Trump attorney Rudy Giuliani was paid $500,000 in 2018 for legal consulting work he completed for Lev Parnas, one of his associates who was arrested on campaign finance charges last week, Giuliani told Reuters on Monday.

Parnas and Igor Fruman were also reportedly involved in Giuliani’s efforts to pressure the Ukrainian government to investigate former Vice President Joe Biden.

Giuliani confirmed to Reuters that Parnas’ company, Fraud Guarantee, approached his law firm in August 2018 for legal advice on regulatory matters, Reuters reported.

Several outlets have reported that federal prosecutors are looking into Giuliani’s relationship with Parnas and Fruman.