A security guard observes a fellow guard making subjective and biased statements in an incident report regarding a confrontation with a visitor. What ethical and professional obligation does the observing guard have?

1. To publicly confront the colleague and accuse them of bias in front of other staff.
2. To immediately edit the colleague's report without their knowledge or consent.
3. To ignore it, as it is not their report or responsibility.
4. To privately address the issue with the colleague first, and if not resolved, report it to a supervisor, emphasizing the need for factual and objective reporting.