You know what, I don't think I'm buying the crime scene was all cleaned up explanation. This is an international terrorism investigation with 2 score people injured, 15 dead. No. The investigators might find new evidence that
requires them to go back. It could happen. At a minimum they should have kept the press out. This is a major screw up.
And the family has hired a true screwball, conspiracy nut full on

attorney.
Let's say you're right, that they did screw up.What possible evidence left behind could be used in the future? The FBI has the electronics, the weapons, the dead shooters, the pipe bombs, the bomb making equipment and anything else they would use. No one is going to court, they are dead. If it's a conspiracy, the electronic data and crime scene evidence collected will bear all that out.
So what evidence is in that house that could be helpful in two months? Hit list hidden in a potato?
DD, I don't know. I know you got your information first hand, so I don't doubt that, but your friend/colleague has seen this done in a
terrorism investigation? - It just seems kind of crazy to me to completely waive all opportunity to go back, check for new fibers, new fingerprints, hair, skin or DNA, pictures, anything. The feds have completely waived it. Actually it seems somewhat reckless, hypothetically, what if they find out another person was involved in the bomb scene, what if they want to go back to find those specific prints, what if there is some odd chemical or material that arises in the course of the investigation, you would personally waive your ability to ever, ever go back and see what else is there if you wanted to by letting the entire scene be contaminated?
The assistant FBI director says that there is an ongoing terrorism investigation and says he released the house to total contamination all in one breath.
1. You are assuming they don't have all the DNA and other evidence they need. This isn't 1985 like I said before, and this isn't some damn police outfit from Bum####, Wyoming. It's the FBI, they do this every day on the biggest cases in this country. Drug cartels, murder for hire, terrorism, mass shootings, serial killers, etc.
2. You are assuming that because it is a terrorism case that it is somehow more inherently difficult than any other case. It isn't. Try a case over the course of months/years with wiretaps, bodies, drugs, and weapons. This is nothing, and no less than 24 FBI agents were on scene in Cali.
3. The perpetrators are dead, meaning no court. That is huge. That means their threshold for evidence is much lower, but this is not to say they didn't get everything they needed.
4. You don't know how they clear the house, gather evidence, or what equipment they use.
5. The garage was off limits to the press, not sure by whose order. That seemed to be the center stage of the evidence.
The guy I called was undercover in biker gangs and in murder for hire investigations, he's got 20 years as a federal agent and feels comfortable with what happened today. The most important evidence is likely the electronic communications, the bomb material, the guns, and those people who had contact with the shooters. That will all be run to ground, and there will be absolutely no reason to go back to the house.
Like I said earlier, arson crime scenes with bodies is probably the most challenging crime scene. Ask yourself this. Once the investigation is over what happens to the scene? It's knocked down, sometimes within days. They can't go back to get any more evidence or information, that's why they are so damn thorough the first time.
I've worked several federal investigations in the last 18 months, but I will admit I know little of the FBI's processes, outside what I saw at the Baltimore riot scenes. But the people I work with say the FBI although arrogant and self-important, are really good at police work. I'll take their word for it.