Of course the defense is going to argue that his rights were violated. It doesn't matter whether they were violated or not, but they have to argue the question and have the court make a definitive ruling. If they don't, the whole thing will be declared a mistrial later on with better lawyers.
So yes, the defense is attempting to prove that law enforcement were convinced there was no lingering threat after an hour of questioning, and that the last twenty hours were unnecessary.
They may well be wrong. It may be that the defense thinks, in hindsight, that law enforcement had enough evidence to know there was no further threat, but at the time of the bombing I don't think anyone ratcheted down the tension to the point where everyone felt completely safe in the first 24 hours after the defendant was caught. And I doubt they were particularly convinced that they were alone. They continued the investigation into their past, their associates, etc for a long time to determine if they were part of a cell, under orders, or had some sort of leadership or guidance that suggested a continued threat.
Yes, the defense is going to argue that this mans rights were violated.
Good.
I do not want any sloppy work done that would possibly jeopardize the conviction down the road. I doubt the judge and prosecution want anything overlooked either.
If there was misconduct, call it out, throw out the evidence, and use what's left.
It's enough, and whatever is decided needs to stick.