Definition: a Case Study is a summary of a problem situation that invites the student to recommend action based on analysis.
A CS is teaching material, not a journalistic or historical record.
The writer of a CS aims to create a learning experience for students by re-creating the problem setting as decision-makers saw it at the time. Although a CS is necessarily an abstraction of reality, a good one will throw students into the same setting as prevailed historically to let them wrestle with the same dilemmas, and perhaps even err - all with the purpose of helping the students learn to avoid a similar mistake in professional life.
Is the object of study in the Case Method.