A federal grand jury issued an indictment against Sen. Bob Menendez (D-NJ) on Wednesday on charges involving conspiracy, bribery, making false statements, and using his influence as a U.S. Senator to benefit the business interests of a friend and donor.

Menendez has repeatedly insisted that he will not resign from office and has maintained that he is innocent of the charges against him. According to a CNN report, Menendez’s attorneys have been in close contact with the government and could be negotiating terms that would lead him to surrender to authorities.

“Federal officials and Menendez’s attorneys have discussed plans for the New Jersey Democrat to turn himself in before a planned court hearing on Thursday, according to people briefed on the case,” CNN revealed.

The government’s case, as first reported by CNN last month, centers on Menendez’s relationship with Salomon Melgen, a Florida ophthalmologist who the senator has called a friend and political supporter. Melgen and his family have been generous donors to the senator and various committees the senator is associated with.

The criminal charges are expected to be filed Wednesday, but the government’s plans could still change.

The charges against Menendez stem from allegations that his friend and donor, Florida-based ophthalmologist Salomon Melgen, benefited from the New Jersey senator’s patronage. Menendez allegedly took private plane trips with Melgen to the Dominican Republic in 2010 but failed to reimburse him for the $58,000 flights until 2013 when those trips were uncovered by investigators.

“Prosecutors also are focusing on whether Menendez broke the law in advocating for Melgen’s business interest in a Dominican Republic government contract for a port screening equipment,” CNN reported last month. “The U.S. Customs and Border Protection agency, at the time, considered donating port screening equipment to the Dominican Republic, which would have hurt the contract of Melgen-controlled company.”

Menendez is also alleged to have argued on Melgen’s behalf with federal Medicare administrators who accused the eye doctor of overcharging the government for the services he provided to Medicare beneficiaries.

According to the Associated Press, Melgen may also soon face his day in court. “A person familiar with a Justice Department investigation says prosecutors are moving toward charging a Florida eye doctor over his dealings with New Jersey Sen. Bob Menendez,” AP reported this week.

The person said prosecutors are expected to bring criminal charges soon against both Dr. Salomon Melgen and Menendez. The person insisted on anonymity because the person was not authorized to discuss an ongoing investigation on the record.

Justice Department spokesman Peter Carr declined to comment Monday.

Some have suggested that the Department of Justice only began to seriously target Menendez when it became clear that he had become the leading Democratic voice in the Congress opposed to the reported terms of a nuclear accord with Iran. But with the deadline for a framework agreement having come and gone, it’s looking as though Menendez might not have a deal to scuttle.