According to Metro news a member of the Muslim community reported the Manchester bomber years ago and nothing was done, that’s because nothing could be done. While communication is certainly one of the key factors in solving the problem with radical Muslims reporting someone for odd behaviour isn’t. In a free country like the U.S. or the UK police usually can’t do anything until an actual crime is committed. The issue then becomes one of getting a person who is talking about hurting themselves or other people the professional care they need but unless a person has been declared incompetent they have to want help.
So while it is noble and responsible to report a potential problem to the professionals there isn’t much anyone can do directly. Until we are perfect beings there will always be violence and neglect that allows violence to happen. Only due diligence from security and law enforcement professionals can help mitigate it, but we are not completely powerless. The Global Economic Symposium generated a wonderful, intelligent list of solutions to terrorism in 2008:
All of these are great ideas and should be implemented worldwide but they are lofty, and unrealistic at this point in human history. As individuals we can vote for leaders that support these kinds of initiatives and change will happen, even if slowly. On an interpersonal level encouraging those we are concerned with to seek professional help is our only real option. If bad things do happen then supporting the victims and maintaining our freedoms and our democracy guarantees we do not and will not let the bad guys win.