Handyman looking for advice

[kemon]

Hello everybody I'm new to this place wish i had known about it before but I guess I didn't have a big enough issue to go searching online for advice. I'm a handyman / I do apartment maintenence and renovations. Done my share of service plumbing in the past everything from snake lines to slab leaks. That said the current problem is a slab leak, the place I'm working in is a 4plex built in the early 60s, however this time it seemed to be coming from under the tub so I removed it and followed the source to understand we r the tiles it seemed but once I lifted the tiles and turned the water back on it isn't leaking anymore and I don't know what to do I can't reinstall a tub until I fix it I'm trying turning the water on and off repeatedly with no luck so far if anyone could help it would be appreciated

 

[MicEd69]

Pictures would be a big help. Could it have been the lines to the tub faucet above the slab? Could it have been the drain lines from the tub?

 

[havasu]

A slab leak will not go away. I'd look elsewhere.

 

[Geofd]

You could dye the drain to see if you get color anywere