-- TW.. my four year old claims assault

I don't know if I need reassurance that I'm doing the right thing or just wanna know if someone else has been here..

Out of no where my daughter told me that she likes to spread her peepee (vagina) for men.. she's four..

I continued to question her.. and she came out saying "person" comes into the bathroom when she's going potty and touches her with a pocket knife..

We took her to the hospital to be looked at (they found no evidence) and they started an investigation..

My biggest concern is the person in question is a family member and I'm terrified of blowing their entire life up in the case this isn't true..

I don't know what to do.. I'm at such a loss.. did I do the right thing by going to straight to authorities or should I have questioned the suspect?!

Help me..