Water leak in master closet attached to master bath?

I have a water leak in the master closet where the floor attaches to the wall. The plumber located the manifolds and there was no water there. He concluded there was a slab leak. I am not convinced. Then last night I noticed the A/C vent dripping (also in the master bath) with a water stain around it. There's another water stain on the ceiling about 6 inches from the vent. The condensation pipe outside doesn't have any water dripping from it. HELP!!