The pickup occurred because the agency filed a petition for removal in court, and a court granted the petition. Somebody knows what happened, even if the person with whom you spoke did not. This could be a SNAFU based upon DCF's mistakenly believing that the child was not in the care of the surviving parent.

If the child has not already been returned.... If you have not already been informed of the court and given a court date, get the court information from DCF and get a copy of the petition, either from DCF or the court, then consult a lawyer with that information. If your assets are limited, inquire with the court about whether you qualify for a court-appointed lawyer. Don't miss any court proceedings.