Bomb threats are common. Most alleged bomb threats also turn out to be fake. While done for various reasons, they serve as an effective denial-of-service attack and waste lots of manpower and resources.
Have there ever been any bomb threats where real explosives were found to have been planted, or led law enforcement to a suspect with an explosives stash or the capability/knowhow of making explosives? I am skeptical, because it seems counterproductive for a genuine bomber to tip off the authorities that there is, in fact, a bomb ready to go off.
I am not asking about a terrorist group making a vague threat to kill or blow up their enemies, I'm referring to threats made for a specific time and place.