Water Damage in the House

Ugh. Water damage to the hardwood floor in the office and the marble tile in our master bathroom. The "mold" spot on the baseboard backs onto the bookcase we pulled away from the wall (3rd picture). Our contractors were here Wed (didn't have tools to cut into wall) and Thurs when they cut into the wall in the office. The backside of this wall is the master bathroom shower. There was no sign of leakage from the pipes. He crawled into the subfloor and there is no evidence of moisture under the shower drain or anywhere. He looked in the attic and there is no evidence of water. Right now the suspicion is the shower pan is not water tight and there is a slow leak out of the shower pan. The shower pan was hot mopped (tar) and flooded for 24 hours before an inspector came to see/verify it was water tight…3.5 years ago. I'm afraid the repair of this mysterious water leak is going to be extensive. The floor is buckled in the office, the tile in the bathroom is buckled and now I found the floor in the master bedroom near the utility closet (on the other side of the toilet) is buckled also. Last, I *think* the floor by the refrigerator is also buckled. Argh argh argh.