The investigation for authorities so far had become an easy job, after every blast, catch hold of few Muslim youth put them behind bars and then try to generate the evidence, if possible.
http://ummid.com/news/2011/November/10.11.2011/ruining_innocent_lives.htm
http://ummid.com/news/2011/November/10.11.2011/ruining_innocent_lives.htm