Most people have touched on anything I really felt the need to comment on so I'll just throw this in there.
*why would he inform them of bombs in his appartment if he wanted to kill people?
He had turned music up to an obnoxiously loud volume in his apartment expecting his neighbors to call the cops. What was supposed to happen:
Cops would arrive, knock on door, no one would answer, cops would proceed to enter the apartment. Upon entering, bombs were suppose to go off.
The point? This was all suppose to happen prior to the shooting taking place.
If bombs went off in an apartment building, you better bet cops, bomb squads, and such would be heading that way. This would create a diversion and let the movie-theater shooting go on for a
much longer time.
Cops were tipped off about the bombs in the apartment when Holme's let something slip about his apartment building. When he was arrested, he assumed they had gone off while they hadn't.
Also, on a side not. Everyone talking about "eye-witness" reports. Only thing I'd like to say is that most people completely lose control (and I don't blame them) in scenario's such as the shooting. There is gas throughout the theater, the movie is still playing, gun shots are going off, people are screaming. People are either fending for them selves, or trying to protect the one's they love, most aren't thinking about looking for the guy, but trying to survive. You are over-estimating an individual's courage and self-control to think that normal (as in non-trained) people are really going to be paying that much detail to what's going on.
If you provide me a more "credible" source for an eye-witness, I will read it and give a second-opinion.