Summarize what happened. (Remember you are writing for the reader. Assume the person who reads your essay has no knowledge of this beyond the Marathon bombing.)
Those of you who are not located in the USA may have to do additional work if you do not know about this situation.
What are the ethical implications of the situation?
Describe the different participants and their responsibilities in what happened. (Participants here may be organizations, firms or individuals.)
Can anything be done to prevent this from occurring again? What can be done?