(CNN) A federal judge denied an associate of Rudy Giuliani's request to lift house arrest and GPS monitoring as part of his bail condition at a hearing Friday. Prosecutors also signaled the brother of Igor Fruman, who's accused of funneling foreign money to US campaign coffers, "could be involved" in the alleged campaign finance scheme.

A lawyer for Fruman, the Soviet-born emigre, asked the judge to remove restrictions that required Fruman to remain inside his Miami apartment, saying it was "completely false" that his client was fleeing the country when he was arrested last month with a one-way ticket to Vienna at Dulles International Airport outside Washington, DC.

Fruman and Lev Parnas last week pleaded not guilty to four criminal charges: conspiracy to violate the ban on foreign donations to federal and state elections, using straw donors to hide the true source of campaign contributions, making false statements and falsifying records to the Federal Election Commission.

Prosecutors said if Fruman was released from home detention, there was the risk he could get on a plane or a boat before authorities could track him down. Assistant US Attorney Nicolas Roos detailed how the day after Fruman and Parnas were subpoenaed by Congress they booked a one way ticket to Vienna that was leaving less than 24 hours later.

The men were arrested on the jetway at Dulles as they were about to board their flight. He added that their final destination wasn't clear.

Since January 2018, Roos said, Fruman had traveled 15 times internationally, sometimes on private planes and often taking circuitous routes. As an example, Roos said Fruman once flew to a small Canadian city but returned to the US from Spain.

Todd Blanche, Fruman's lawyer, said the men often booked their flights last minute and would choose one-way fares if they didn't know their schedule. He added that the price of the one-way ticket to Vienna was $8,000 compared with $20,000 for a round-trip ticket.

Roos said Fruman had ample resources overseas and political connections that would make it easy for him to find refuge in the Ukraine.

Roos handed the judge and Fruman's lawyer a photo copy of a brochure indicating Fruman was chief executive of a Otrada Luxury Group, which owns Buddha Bar in Kiev and hotels, restaurants and a beach club. Fruman, he said, "could return to Ukraine where he is politically connected and can decide never to come back here and live a very nice life."

He added that in the past three years $21 million passed through FD Import Export, a company Fruman runs with his brother, and there were substantial financial resources that Fruman didn't disclose to authorities. Roos said, "international wire transfers used to fund the foreign contribution passed through the defendant."

The judge said he was persuaded to keep the bail conditions because of the one-way plane ticket and the business and political connections Fruman has in the Ukraine.

The brother

At the bail hearing prosecutors revealed that their ongoing investigation could ensnare Fruman's brother, Steven. Last week CNN reported that Steve Fruman was subpoenaed by prosecutors.

Prosecutors said they raised concerns about Steve Fruman signing his brother's bond last month when he was initially arrested and posted bail in Virginia. Roos said they told Fruman's lawyer that it appears that Steve Fruman "could be involved in some of the conduct charged in the indictment."

Roos said the government needed more information because Fruman's brother may have lied when he was interviewed to try to conceal certain bank accounts and sources of income he had. One of the businesses, he said, may be connected to the crimes charged in the indictment.

Judge Paul Oetken said if someone is connected to the alleged crimes, he's probably not a good person to co-sign the bond. Roos said prosecutors were trying to "evaluate" if Fruman's brother is linked. Fruman's attorney called it a "fishing expedition." The judge gave Fruman until next Friday to meet his bail conditions.