This question is very vague but I will try to answer it for you. Of course, if it is true, then generally anyone can make any statement they want. For there to be a case of defamation or slander, you would have to prove that the statement was knowingly false and that it caused you damage.
Unfortunately, it is legal, especially if it was said in good faith. That is, if the investigator has enough probable cause to file another accusatory instrumet in court for differnt charges, then the investigator can do that, and making that statement is then just a verbal declaration of what the investigator is saying that he might do. In fact, if the investigator has sufficient evidence he could do so right away, the court would then arraign you on the ne charges, and th court could tehn set a new bail amount in addition to the one alreasy set.
On the other hand, if the investigator does not have such evidence and is just blustering, it would seem rude and crude but still not illegal, in fact polcie officers routinely lie to defendats in hopes of getting them to make admittions against themselves.
Only if teh investigator actually did file accusatory instrumetns knowing that they are based on lies has he commited an offense. probably offering a false sworn instrument
