Jeopardy attaches when a witness is sworn.
Wis. Stat. § 938.317
Jeopardy
Known as the The Juvenile Justice Code
The act spans §§ 938.01 to 938.9995 (127 sections).
1995 a. 77.
Official source: Wisconsin State Legislature. Reproduced from public-domain Wisconsin statutes; confirm against the official source for the current text. Not legal advice.