special ed makes a good point. This is no longer he said/she said, now that Angel is claiming to know the truth. Since there are no Miller-type roles (there aren't, are there?) this means either two Scum are throwing themselves onto the fire, or they are telling the truth.
At this stage I see it as a strong chance we had a Power Role out a Scum, and they desperately tried to drag said power role down with them. It is a good gambit to play when cornered, after all.
Unvote Vox
Vote Ulla
If Ulla is innocent, we go Scum hunting.