You must immediately file a petition for divorce and seek emergency temporary orders granting you primary placement. Once there is a court order, the police can help you. The longer you wait to file, the more you compromise your rights. Once she has been living in a county for thirty days (assuming she is still in Wisconsin), she can file for divorce in that county.
This answer is for informational purposes only. By answering this question, no attorney/client relationship is created. Although the legal information is accurate, it may not be appropriate for your situation. The best way to handle any legal problem is to seek the advice of an attorney.
You MUST hire a lawyer experienced with these cases immediately. These cases are always concerning, and I would be happy to help you. My office is in Baraboo, and I can consult with you on Monday. Certainly, filing a divorce now is necessary, with a request for temporary order. I would also contact the police, both here, and in any other place you think she may be. They may be of some help, at least to help you locate the children. When you say you have equal rights, I am not certain if you mean you have some type of court order already, or if you simply mean that you are the legal father. Depending on where you think she may go (even out of the country?), there may be other actions to take to notify the proper authorities are prevent a worse situation.
I have dealt with these situations several times, including in Sauk County court, and it is absolutely vital that you do everything you can now to get the children back. There are certain situations where your wife can move to a different state and immediately begin an action for custody of the children in that state. That would be extremely difficult and costly for you to defend. I highly recommend that you address this immediately.
This submission is not, nor is it intended as, legal advice. You should consult a lawyer to address your legal issue.
There is something wrong here. Taking a child from a parent and hiding them is kidnapping, or at a minimum parental interference. The sheriff should not allow that to occur unless there is something else wrong. Like, Paternity (never married), TRO, Domestic Violence, Criminal claims against you. Usually the sheriff will not hide information just for a divorce filing (if she has already made one). So, there is something else wrong.
Call the desk officer on duty at the sheriff's office and ask why they will not let you know where your children. File a formal request for police reports and notes.
Getting a local attorney can turn that all around for you.
You can file for Divorce, but any of the above reasons may not get your children back as soon as you would like.
WALWORTH, ROCK and JEFFERSON County Divorce/Family Law Attorney - Atty Richard Missimer does answer questions on Avvo strictly to be helpful but these do not constitute legal advice. These answers do not establish an attorney/client relationship. If you would like my help and are within my practice area, contact me at (262)565-8200 for a FREE CONSULTATION.