re: Slab leak detection - plumber recommendation?

This is after I started tearing up the floors. You can see a dark line that I circled in red. I’ve also been taking FLIR images and spray painting where it appears damp. That’s the black mark. Most of the time, the FLIR is picking up cooler areas around cracks in the slab. I’ll have to upload that later. But the FLIR cooler images are not following the straight line where the wood was rotten. They’re usually very close to it.

Also, there was an addition to the house before I bought it. That red circled area is also where they tied in the new slab