MILWAUKEE - There are a lot of questions about why State Senator Lena Taylor "took the 5th" court.

Taylor showed up to Milwaukee County Court Friday afternoon as part of what's called a "John Doe" investigation.

It's the state equivalent of a Federal grand jury, where witnesses are called to testify in a criminal case, on the record, but those records are sealed.

We do know, that as part of this criminal investigation, Taylor asserted her 5th Amendment privilege and refused to answer questions that might incriminate her.

We know Taylor is involved, because a judge granted the prosecution's request, in open court, that Taylor be given immunity, presumably so she'll cooperate with prosecutors and answer their questions.

Since the case is sealed, no one involved in it is allowed to talk about it, but Taylor did issue this statement:

"I have been advised by the judge that I am a friendly witness in this John Doe proceeding.  I am not the target of this investigation and invoked my 5th amendment rights at a prior hearing in an abundance of caution.  At the conclusion of this legal proceeding I will have much more to say about this matter but until then I have no further comment.”

Often "John Doe" investigations lead to criminal indictments, but at this point, we don't know who the investigation is targeting, who the other witnesses are, if any, or why Taylor seemed to be so worried about incriminating herself if she told prosecutors what she knew.

TODAY'S TMJ4 will have more details as they become available.