Jonathan Ernst/Reuters

Federal prosecutors are ramping things up in an investigation related to President Trump's personal lawyer Rudy Giuliani, The Wall Street Journal reports, and there may be a whole bunch of charges awaiting people involved, though it's not clear why Giuliani personally falls under the microscope.

Subpoenas have been issued to people with ties to Giuliani and his associates, Igor Fruman and Lev Parnas, as part of an investigation led by the Manhattan U.S. attorney's office and the FBI. Fruman and Parnas, two Soviet-born American businessmen who have allegedly aided Giuliani in his quest to find compromising information on Trump's political opponents in Ukraine, have already been hit with campaign finance charges, to which they've pleaded not guilty.

The latest round of subpoenas reportedly seek information on Giuliani's security-consulting firm, Giuliani Partners, which the former New York City mayor founded in 2002, and a company founded by Parnas that paid Giuliani for business and legal advice. Giuliani said he was not contacted by prosecutors himself and denies any wrongdoing.

Among the charges reportedly under consideration in the subpoenas are obstruction of justice, money laundering, conspiracy to defraud the United States, making false statements to the federal government, serving as an agent of a foreign government without registering with the Justice Department, donating funds from foreign nationals, making contributions in the name of another person or allowing someone else to use one's name to make a contribution, along with mail fraud and wire fraud. Read more at The Wall Street Journal.