Do I have to cooperate in a child abuse investigation?

The Cuyahoga County Division of Children and Family Services in Cleveland contacted my boyfriend and me about a child abuse investigation regarding my mom. She runs a daycare out of our house and apparently one of the kids says he was abused by another kid at daycare. They want to talk to my boyfriend and me because we live there. Can we refuse to talk to them? I don’t want to get my mom in any kind of trouble. I told them I wasn’t comfortable talking with them without a lawyer and they said it was ok to have one at the interview if we do agree to answer their questions.