During a routine monitoring of your organization's network, you identify a potential breach. Following an investigation, you discover that sensitive company data, including login credentials, has been listed for sale on a dark web marketplace. Which of the following actions would best assist in the immediate mitigation and investigation of this issue?
Keep monitoring the dark web marketplace for any activity regarding the sale or purchase of the company's stolen data.
Isolate the compromised systems and initiate a forensic analysis.
Notify the internal security team and all company stakeholders about the breach to ensure wide awareness.
Begin digital forensic investigation without isolating the systems to acquire real-time data.