Where is this in the Constitution? The Constitution is the supreme law of the land, and federal statutes are subject to the limitations in the Constitution.
Also, there is a federal law that states federal officials can have their criminal cases removed to federal court if arrested by a state law enforcement agency during the performance of their official duties. Not sure how the Feds could force a state to release an accused federal official if the state refused to do so.
I pity the fool who is sent to confiscate the abundance of fire arms along the Texas/Mexico border. They should check with the Census lady who was almost killed by a watch hog, a javelina trained to attack anyone who came to the door of a mobile home parked out in the desert.
The hombres who inhabit that no-man’s land have creativity. No one would ever find the bodies.