You cannot record the babysitter's conversation with the police without either the consent of the police or the babysitter. You can record conversations between yourself and the babysitter and/or police, without the consent of the babysitter or police.
New Jersey is a "one party consent" state, meaning as long as you have the consent of one party to a conversation it can be recorded. You would count as one party, so you can record your own conversations with others, without their knowledge or consent. Keep in mind that if you are recording a telephone conversation with someone in another state you may be violating federal or state laws outside of New Jersey law. Additionally, keep in mind that there are various restrictions, such as prohibitions against recording devices in most New Jersey Court Systems. Further, there are rules governing specific situations, such as "nanny cams".
My comments on your inquiry are based on the limited information provided. If you have any additional information which you feel could impact my understanding of your situation, please feel free to provide. Nothing in my comment, including the comment itself, constitutes an attorney-client relationship. This is an informal advice forum for general informational purposes only.
It is illegal to record someone without their knowledge. You would have to inform them that you are currently recording the conversation.
You should consult an attorney for advice regarding your individual situation since every case is different and not all information is relayed in an online question. The Law Office of Ophelia Bernal-Mora, P.A. is a family & criminal law firm located in Orlando, Florida, we invite you to contact us and welcome your calls at 407-354-5223. Contacting us does not create an attorney-client relationship. Please do not send any confidential information to us until such time as an attorney-client relationship has been established.
Be very careful. You are permitted to record any conversation you are a party to. You CANNOT record the conversations of other people.
This post is not legal advice and does not create a confidential attorney-client relationship. It is being offered for informational purposes only. You should not relay any confidential or priviliged material in this public forum. You should not rely on this post as legal advice. In order to obtain a more comprehensive answer to your question you should consult with an attorney of your choosing.
Sign up to receive a 5-part series of useful information and advice about child custody law.