If they have information on possible issues in the home, I believe they usually just show up. If a report has been made you have the right to know that but not who made it generally. I hate this system. I have known too many vindictive jerks that made false claims-and even if unfounded-the fact a claim was made stays in your record.. Totally unfair. People who do this should be prosecuted with a felony charge. Anyway, I can see they may not tell you who called-if someone did-but seems they should tell you why at least. However getting too defensive isn't a good idea. Just make sure house and kids are clean and well fed, and show them there are no concerns. It may be a good idea to just consult with an attorney-most will do a free consult-and a family law attorney could let you know your rights and what to expect. Good luck!