Answer:
Commanding officer.
Step-by-step explanation:
Commanding officer can be defined as any individual who works with the armed forces and is in charge of a group or operation in a military unit. They are saddled with the responsibility of providing guidance and acting as a role model or example by being morally upright, confident, positive and dominant to their subordinates.
Hence, the decision to investigate if alcohol was a contributing factor to an incident rests with a commanding officer.