I used to work for a District Attorney here in my city and I worked Grand Jury - the GJ has a wide leeway to hear any and all evidence that the LE/State's attorney wants to present. There is no "defense" objecting to evidence, fighting to get evidence thrown out, etc. The GJ will hear testimony from many, many witnesses that the SA wants to put in front of them to make sure they get a "true bill" which will bind them over to stand trial once formal charges are brought. Also, GJ members have the option of asking to hear testimony or see evidence from anyone they deem necessary to answer any questions THEY may have. Like I say, it is a wide berth to hear MUCHO evidence that LE has.
There is NO WAY a GJ won't indict KC.