Here is what I got from a google search on the statute of limitations in Wisconsin looks like about 6 years.
Felonies, with a few exceptions: within six years
Misdemeanors, with a few exceptions: within three years
Adultery, with a few exceptions: within three years
First-degree intentional homicide, first-degree reckless homicide, felony murder, second-degree intentional homicide, first degree sexual assault of a child, certain felony violations of engaging in repeated acts of sexual assault of the same child: no limit
Second-degree reckless homicide: within 15 years
Theft, having obtained possession of the property lawfully and subsequently misappropriating it: within one year after discovery of the loss, but time limitation can be extended only up to five years
Second degree sexual assault of a child, certain felony violations of engaging in repeated acts of sexual assault of the same child, intentionally causing great bodily harm to a child, sexual exploitation of a child, incest with a child, certain child enticement, use of a computer to facilitate a child sex crime, soliciting a child for prostitution, sexual assault of a child placed in substitute care, or sexual assault of a child by a school staff person or a person who works or volunteers with children: before the victim reaches the age of 45 years, with exceptions relating to the use of DNA evidence
Certain causation of bodily harm to a child or failing to act to prevent bodily harm to a child, causing mental harm to a child, and certain child enticement: before the victim reaches the age of 26 years, with exceptions relating to the use of DNA evidence
Trafficking of a child: before the victim reaches the age of 24, with exceptions relating to the use of DNA evidence
DNA evidence
For certain offenses, use of DNA evidence to identify the offender can extend the periods of limitation for prosecution (see Wis. Stat. § 939.74 for more details)
Tolling provisions
Time periods during which the offender was not publicly a resident of Wisconsin or during which a prosecution against the offender for the same act was pending are not included in the periods of limitation
Time periods during which an alleged victim of sexual exploitation by a therapist under is unable to seek the issuance of a complaint due to the effects of the sexual contact or due to any threats, instructions or statements from the therapist are not included in the periods of limitation