The existence of a fiduciary duty is a question of law for the court to decide, while whether a breach of fiduciary duty occurs is a fact question. Scanwell Freight Express STL, Inc. v. Chan, 162 S.W.3d 477, 481 (Mo. 2005). So, in any fiduciary litigation, there are two main steps: (1) establishing that a fiduciary duty exists and (2) factually that a breach of that duty occurred.
A fiduciary relationship may be legally established when “one reposes trust and confidence in another in the handling of certain business affairs.” Id. at 481. Assuming this relationship exists, it is up to the judge/jury to decide if the facts support a breach of that duty. Finally, if these two elements are proven, then a plaintiff needs to prove causation and damages.
Fiduciary litigation — eg, breach of trust — is legally complex and can be quite involved.