In which scenario does jeopardy first attach in a non-jury trial?

In a non-jury trial, jeopardy attaches when the first witness begins to testify. This signifies the formal start of the trial proceedings, where evidence is actively being presented in front of the judge. By beginning the testimony of the first witness, the court is fully engaged in the trial process, marking the point at which the defendant is at risk of conviction.

Other options, such as a pre-trial conference or a guilty plea, do not signify the attachment of jeopardy because they occur before the actual trial proceedings begin or do not involve the essential element of a trial process where evidence and arguments are actively being presented. In a non-jury trial, the judge acts as both fact-finder and arbiter, which highlights the significance of when testimony begins as the moment that jeopardy officially attaches.