Legal Question in Family Law in California

I'm afraid the constitution says no such thing. Childrens protective services agencies are not only permitted, they are mandated to act on credible reports of child abuse or endangerment, even if they later prove false.

And whatever they think your husband did, if he actually did it, and you knew about it, you should probably start looking for an attorney for yourself.

The Constitution has no explicit language regarding parental rights. These rights are considered by the Supreme Court as fundamental and protected under the 14th Amendment Due Process Clause. That is, any government action interfering with your way of raising kids would be subject to strict scrutiny and you will be afforded procedural and substantive due process of law. However, that is not saying the government agency like dcfs cannot take action like this. The state has compelling interest to protect children in its territory. However, I would question the constitutionality of such action if, as you said, they did not speak to you, interview you, or meet you in anyway.