The story that Bruce Ivins was the anthrax attacker came out with a bang, surprising, I think, everyone. I find the idea that the attacks were an inside job appealing, because they tie up the strings of how someone would get the equipment and expertise, and how they would smuggle the anthrax into the country if it were made overseas. The evidence is circumstantial, but of course the evidence in a case like this would be... Yet doubts remain.
Taking into account my never having worked in a biodefense lab, I think it might be worth noting some things about scientists in general that shed light on this case.
1. Scientists are really bad at security. Without compromising the security of my own lab, the only thing I can say is that passwords are routinely left lying around becuase people routinely log into one another's computers to get old data, DNA sequences, etc. etc. Getting scientists to lock up the lab is a major issue. Labs that routinely collaborate will exchange keys so that people can get into each other's freezers and borrow materials.
Depending on security at Detrick, either it was really hard to get into the anthrax wing, yet once inside one could move freely, or it was hard to get in and one needed different codes to get into different labs. Even if the latter case was true in theory, the more open case would likely pertain in fact with people moving between labs with impunity. Moral: Just because something is in your lab doesn't mean you're the only one with access.
2. Most scientists are disorganized. Most obviously in their lab notebooks, but also in keeping their vials of stuff arranged, whether they be flies, DNA vectors, or anthrax cultures. Did that culture get here 9 years ago, or did we get it as part of the forensic work 7 years ago? The poor hand-writing of most bench workers means that going through an old lab mate's notebook looking for details on some bit of DNA they constructed is a crapshoot. Many experiments will be completely ignored if they failed. Non-frost-free freezers fill with ice and tubes get lost in the permafrost. Material gets moved form project to project or from lab to lab depending on who thinks they might need it next, not on where it makes most sense. Moral: Just because something is in your lab, it doesn't mean you know about it.
3. Wet work looks like wet work. Which is to say, the guy at the next bench doesn't know whether the bacteria I'm working with are expressing delta sarcoglycan or botulinum toxin. If he sees me growing a large culture, he doesn't know if I'm preparing a lot of DNA to inject into mouse embryos, or to dry out and mail to my congressman. The label says Drosophila-dsg, and who are they to question it.
4. Scientific knowledge is a mile deep and an inch wide. This includes technique. Despite dozens of lab meetings from colleagues talking about cell culture, I couldn't even keep them alive without personal instruction. Even well written books will forget to convey the little things necessary for success (e.g. there is no "any" key). If my lab had a spore aerosolizer the odds of my not breaking it, much less successfully weaponizing anthrax would be very low. This also argues against the defense of a scientist being too clever to leave the clues the FBI relied on. Which will they find more believable - That you didn't recognize what the vial was and burned it, or that you lost it in the back of the freezer? A scientist wouldn't know. A cop would.
5. Living things have their own schedule. Mice are born on Thanksgiving, Taq only goes so fast, I just got back from putting on a primary antibody at 9 at night. So unless you're 2 out of 3 lucky, well organized, or not in a hurry, you'll show up at some strange hours.
6. Scientists are weird. Weird hobbies, weird ideas of the world, weird personnae. Maybe I read Watchtower and don't want anyone to know so I subscribed under an assumed name. Maybe the best Harold's Chicken is in by the DG house in Evanston. If you excluded weird people, all science would be brick laying science, and there would be a lot more intense baristas with 'theories.'
There's not much original here, but I hope it helps your understanding, or perhaps prompts the FBI to be a bit more open.
Any more oversimplifications to consider?