When Venobya returns she lays out where she saw groups of not-your-people. Patches of undead feasting on cultists and tieflings that didn't manage to find adequate shelter in the aftermath of the rout. More worrisome, there are a number of squads which are creeping their way past the gulch and into the streets of the city. In the graveyard there is surprisingly few undead moving about, although the unnatural shadows made picking out creatures difficult.
"And they are eating all the rats that they didn't scare." Venobya says.
Just before you leave the relative safety of the building, Aravashnial comes up flipping through one of his ever present books. "I've found my spell that lets me see the undead aura. Just in case they have a more subtle transformation that we don't know about." A slight pause, "I am certain that you will not need me to use it when you return."