Detect Soul

For the duration, you sense the presence of creatures or objects with souls within 30 feet of you. If you sense a soul in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears a soul. If a living creature lacks a soul a void is viewed instead (a hole in the chest, or where the soul might be located.)

The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.