Tenant could be faking water / leak issue?

[Stefan Mayerschoff]

Short form: I suspect my tenants of "faking" water in the master bath / bedroom. We had redone the entire bathroom while living there, and did not notice any water issues. Tenant has been in 2 years with no water issues, then I get a call that the carpet in the bedroom is soaking wet in the corner (exterior wall and master bath wall). Plumber comes out, says it's the soaking tub located on that wall - the drain is leaking. It gets repaired. Everything is dry, I replace 2 4 foot sections of drywall in the corner just in case of mold / mildew.

Days later suddenly the carpet is wet again, and now magically the shower drain is leaking. Demo 5-6 rows of subway tile and cement board in the shower, pull up the fiberglass pan, have a new drain put in. Waiting for everything to dry from the mold treatment so they can install the liner and do the tile, and I get a call that there is water against the exterior wall after the rain last night, under where the shower floor tile will go and into underneath the soaking tub area.

Not sure what the end game is - the carpet is trashed from their dog, they are wanting it replaced even though it's only 3 years old. They were not happy when I told them I was only going to seam in new carpet where there was potential mold in the corner. They expressed wanting to buy the house down the road when I sell - not sure if that plays into this or not. A buddy of mine checked the house out with me - we can't find any leak points, unless it's magically coming in through the foundation, but only at certain times. We checked the upstairs bath, and the downstairs tub - no water. The shower hasn't been used obviously. We ran the hose outside for a good while - didn't see any water. Not sure how to figure out if they are just pouring water since I am not there 24/7.

Anyone ever have anything like this? Curious what options are available, or how you might have addressed.

Other things of note: Renter now has ex husband living with her full time in the property, even though lease specifies no guests > 7 days without approval (he's been there for at least 2 years per social media posts). Exterior was professionally painted including elastomer caulk fill of any stucco cracks less than 18m ago. Still looks great. Let me know if any other details I left out would help. Thanks!