CLEAN : IMF chief Lagarde named assisted witness

The speaker discusses being heard by the investigating magistrates in a complex legal case involving Burnout, RP group, and Credit Union. They provided information to show their actions were in the state's best interest and lawful. As an assisted witness, they plan to return to Washington to continue their role as Managing Director of the IMF.

What does the status of assisted witness imply in this context?

What is the speaker's position and what is their mission?