The Witchblood: The Veils Universe by L.L. Frost

Nothing says relaxation like a summons to murder.

When the Cleaners are called back from a much-needed vacation, they return to find Clearhelm under attack. Someone is killing the witchblood, leaving empty bodies drained of magic. All signs point to another practitioner as the culprit, but Clearhelm’s coven leader is adamant that none of the members of the Conservatory would risk dirtying their souls with dark magic.
As the number of bodies increases, Pen and her team must track down the killer before all the stolen magic gets out of control and takes Clearhelm with it.

A multi-POV, urban fantasy featuring demons, witches, and messy situations that will leave your toes curled and gripping the edge of your seat.