Well, if the EMTs haven't left the scene yet (hmm, I think there is a pun in there somewhere
), a smart PC could hex the engine (or the power locks on the doors, maybe, or blow out one of the tires) of the ambulance. If they aren't smart enough to think of that, a generous GM could compel a player to do that.
Though convincing the EMTs to let the PCs take a look at the victim may need some social finesse. Theoretically, shouldn't be very hard at all. They'll be sitting there waiting for the next ambulance to arrive. And nothing better to do.
If they have left already, retro-active may be the way to go. Or you could drop a clue or maybe somebody gets smart and tries to scry for the component used to create the sympathetic link used the the Thaum ritual. Or just leave it be. They probably know that somebody is slinging around some bad juju now. Just step it up some more. Maybe, TBBG decides to go after the PCs, or their family. They *did* arrive on the scene to help the victim, did they not?