I thought that double jeopardy protection was absolute (except when the Feds charge you with depriving someone of their civil rights by killing them).
Nothing is absolute. But they have to be able to establish that’s not trying again with a different jury. They need serious Grade A level new evidence, with serious Grade A level possession chain, and a serious Grade A level reason why they didn’t have that evidence available last time. It borders on “only in theory”, but if the right something were to come up they could try again, or they could at least try to try again.