A fourth defendant in the federal campaign finance case involving two associates of Rudy Giuliani, the president's personal attorney, was arrested in New York on Wednesday.

David Correia, an American businessman, was taken into custody at New York's John F. Kennedy Airport. Correia is one of four men charged in an indictment, which also targeted Lev Parnas and Igor Fruman, a pair of Ukrainian businessmen with extensive business ties to Giuliani.

Last week, ABC News reported the business relationship between Giuliani and the men charged in the alleged campaign finance scheme is a subject of the ongoing criminal investigation being conducted by federal authorities in New York, according to two sources familiar with the matter.

Andrey Kakushkin, a Ukrainian-born business associate of Correia's, was taken into custody last week in California. Parnas and Fruman were arrested last week at Washington Dulles International Airport in Virginia, just outside Washington, as they attempted to leave the country with "one-way tickets," U.S. Attorney for the Southern District of New York Geoffrey Berman said.

With Correia's arrest, all four defendants are in custody.

The indictment, which was filed on Oct. 10 in the Southern District of New York, alleges the defendants "conspired to circumvent the federal law against foreign influence by engaging in a scheme to funnel foreign money to candidates."

Court documents describe how the four defendants allegedly funneled "$1-2 million" from a Russian donor into the U.S. political system between June 2018 and April of this year.

Correia and Kakushkin are expected to appear in a New York federal courthouse on Thursday for an initial appearance. None of the defendants have entered a plea.

Authorities said last week the investigation is ongoing.