If Trump does hold another nations passport, guessing the same nation as much of congress also have duel citizenship with. Here's a clue for ya all.
The nation in question named a new housing estate after him, established on disputed ground.
I could see him holding onto the diplomatic passport as a souvenir, but if he had read passport, it is the property of the US government and can be reclaimed by them. Having multiple valid passports issued by the US is illegal except for the holders of red cover(primarily diplomatic) passports. The red cover passports are to be surrendered at the end of tour, mission, or term unless extended by competent authority.
I guess he is really pissed that he can't leave the country now unless a country will allow him in as a refugee sans documents.
The Saudis will take him. They kept Idi Amin. Of course they made Idi shut up and stay hidden.
As I heard said, earlier, "Um, if Trump told me he was wearing a red tie, I would doubt the veracity of the statement."
That said, why would the FBI take passports?
With his cash reserves in many off-shore accounts, Tweety is a strong flight risk.