I don't think they know what it means. They referred her for criminal investigation over tampering with witnesses in the Jan 6 case. One of those witnesses is Cassidy Hutchinson, who you recall told us she had to change lawyers because her Trump paid lawyers were telling her NOT to cooperate.
So witness tampering means convincing witnesses Trump was paying NOT to testify, to go ahead and testify. So stopping his witness tampering, is their definition of witness tampering