move might be on law enforcement's part, very similar to what we saw unfold here in austin, texas, not too long ago. where the bomb maker adjusted his plans and targeting an m.o., predicated on the news coverage. >> how much of a concern are copycat attacks. it's something we always think about when reporting on some like this. how often does that happen. >> that's a concern. investigators will look at that. >> there are various manuals on the internet that show how to make bombs. we saw that in the boston bombing investigation. and what the investigators are looking for is what inspired this individual or individuals to try to commit these hain ouls -- heinous acts. what inspired them, we know the al awacky's inspired the internet sites. they will be looking for that as well as technical clues and forensic clues in the bombs themselves.