Ok, if Evelyn is gone then you did advance the plot forward.
The dog in the graveyard can also help you find who did it. By sniffing out clues you bring to him. if you talk to him you will get that option.
Evelyn escaped into her secret Lair. You get info about it if you go into her house in the city, just behind of doctors house. If the doctor is still there he will tell you to go check her house.
She left the key in a small backpack in the room where she was healing those two people.
Otherwise you can break in.
Her secret lair is in the northwest area, that you get to by passing through the cave with renegade Sparkmaster 5000.
And to enter it you need a special "reveal spell" that you can find in her house, among other things.
