The defendant's appeal is dismissed.

1. The summary of the grounds for appeal (misunderstanding of facts) is that the Defendant only sold mobile phone phones to D, and did not commit the instant crime in collusion with D.

2. Determination

A. Article 30 of the Criminal Act provides that two or more principals jointly commit a crime. A joint principal offender is required to establish a joint principal offender through functional control by a joint doctor, which is a subjective requirement, and the joint principal offender’s intent is to jointly engage in a specific criminal act with another person’s intent (see Supreme Court Decision 2001Do4792, Nov. 9, 200). Such joint principal offender’s intent is insufficient merely to recognize another person’s criminal act but to allow it without preventing it (see Supreme Court Decision 200Do576, Apr. 7, 200; 200Do576, Apr. 2, 200). In order to establish the joint principal offender’s crime, there is no need to establish a prior conspiracy of crime plans, which is an objective requirement, and, in essence, it is sufficient to reasonably establish an indirect or circumstantial relation with each co-offender’s constituent element, such as an indirect or circumstantial relation with each other’s constituent element.