More than four years after being indicted—and acquitted—in a corruption case, Sen. Bob Menendez (D-NJ) is facing a fresh probe by federal investigators, his office acknowledged Tuesday. The exact nature of the investigation was not immediately clear, even to the lawmaker himself, an adviser said in a statement. “Senator Menendez is aware of an investigation that was reported on today,” Michael Soliman said, “however he does not know the scope of the investigation.” The news was first reported Wednesday by Semafor, which noted that Manhattan prosecutors have contacted figures in Menendez’s inner circle, with one source saying that at least one relevant subpoena has been issued. Two sources with knowledge of the matter told the outlet that the investigation is similar in a broad sense to the government’s 2017 case against Menendez, but involves a different set of people. The previous case, which ended in a mistrial, focused on his relationship to a Florida eye doctor, from whom the senator was accused of accepting nearly $1 million in campaign contributions and gifts in exchange for political favors.