Garret's soul looks as though it's been tampered with - surgically removed, to be precise. An Attuned person can always tell when a soul's been removed - it's not meant to be, ever, and there's always some kind of feedback.
The culprit would have to be someone with intimate sorcerous knowledge. However, there's nothing to indicate who or what did it - no brand of ownership, no signature, no elder sign. No energy trail back to the original caster, either.