As part of an ongoing sex trafficking probe, the ex-girlfriend of Florida Republican Rep. Matt Gaetz testified before a federal grand jury last week. Her reported cooperation has now earned her immunity. 

Precisely why she would need immunity and for what crimes is at this time unclear. Typically there are two types of immunity: total or “derivative use” immunity. Total immunity is a coverall and prevents a defendant from being slapped with any future charges based on matters related to their testimony.

Derivative use is often more restricted and acts more like a Fifth Amendment privilege, meaning that it can protect a witness from having their statements used against them but it does allow prosecutors to levy charges based on the same crime so long as the charges are based on evidence obtained independently from a different source. 

Again, it is unclear which version of immunity Gaetz’s former girlfriend may have secured. 

The development was first reported by CBS News. A representative for the Department of Justice did not immediately return a request for comment. 

Gaetz has been under investigation by the Department of Justice for several months as investigators assess whether he committed a variety of sex crimes, including paying underage women for sex and traveling with them over state lines while they were still minors. 

Authorities are also reportedly exploring an obstruction of justice charge for the congressman in light of his reported attempt to communicate with one of the alleged witnesses to the crime.