This paper analyzes the role of situational information as an antecedent of terrorists' opportunistic decision making in the volatile and extreme environment of the Mumbai terrorist attack. We especially focus on how Mumbai terrorists monitored and utilized situational information to mount attacks against civilians. Situational information which was broadcast through live media and Twitter contributed to the terrorists' decision making process and, as a result, increased the effectiveness of hand-held weapons to accomplish their terrorist goal. By utilizing a framework drawn from Situation Awareness (SA) theory, this paper aims to (1) analyze the content of Twitter postings of the Mumbai terror incident, (2) expose the vulnerabilities of Twitter as a participatory emergency reporting system in the terrorism context, and (3), based on the content analysis of Twitter postings, we suggest a conceptual framework for analyzing information control in the context of terrorism.