If the domestic offense involves a child or if a child was present when a domestic offense occurred, the police will make a referral to DCF, whether or not the child is a victim in the alleged offense. DCF will then open an investigation into whether there was abuse or neglect of the child and make a determination as to whether abuse was substantiated or unsubstantiated. This investigation will involve a review of the police reports and potentially speaking to the witnesses and/or child. It may also involve a home visit to ensure the welfare of the child.
Keep in mind, just because DCF unsubstantiated an allegation of abuse or neglect, does not mean that DCF is then out of your life. DCF may keep a case open for further involvement if there are recommendations being made to the parents. For example, if DCF wishes the parents to take a parenting case or to engage in treatment because there are allegations of drug issues or unaddressed mental health issues. While you don't have an obligation to cooperate with DCF's investigation, the criminal court may order you, as a condition of your release, to cooperate with DCF and to the extent that you do not, the court may increase your bond or modify your protective order. You should make sure to contact your criminal defense attorney if you receive contact from the DCF.
It is always a good idea to retain a DCF attorney to deal with the DCF investigation, especially if an abuse or neglect petition is filed in court.