What is a significant aspect of the credit union's procedures for SAR investigations?

The correct choice focuses on the criteria for closing the account, which is significant in the context of SAR (Suspicious Activity Report) investigations within credit unions. When a credit union identifies suspicious activities that warrant a SAR investigation, they must evaluate the account involved carefully. This involves establishing clear criteria and policies about when an account might be closed due to risk factors such as patterns of suspicious transactions or the nature of the activity that has been reported.

Implementing concrete criteria ensures that the decision to close an account is consistent, justified, and compliant with regulatory requirements. This step is crucial as it protects the credit union from potential risks associated with maintaining accounts that are linked to financial crimes. This practice not only aids in the investigation process but also ensures that the institution upholds its obligations under the Bank Secrecy Act and other applicable financial laws.

Other options, while potentially related to operations, do not directly address the essential protocol involved in handling situations that arise during SAR investigations. For instance, involving only external auditors would limit internal oversight and knowledge; disregarding member complaints could lead to unaddressed risks; and filing reports solely when mandated by law might neglect the proactive stance that institutions need to adopt in identifying and reporting suspicious activities.