The moment he went to his ex-wife's home to pick up his daughter:

 http://www.imagefap.com/photo/445629830/#22

he knew, something had changed. Her top was lower cut, her shorts were too short, and she walked more like a woman than the young girl she was. When they got to his home she dropped her stuff in the living room and went to the bathroom to shower. Curious, he pulled out her laptop to see if there was anything to see; nothing, everything was normal. Then, he saw it, her phone, laying at the end of the table. He looked through the txt messages until he found what he knew to be the cause of his unease. Her friend; the girl in the picture:

 http://www.imagefap.com/photo/445629830/#21  

texing her things that he knew started this all. The txt messages told him the story: The friend got her high on meth 2 weeks ago, the day after his daughter came home from his house. She talked her ito trying it and his daughter agreed. The txt messages indicated that her and the friend then started watching porn and at some point, the friend showed her some pictures of what she was doing while his daughter was with her mom. The pictures were of the friend, riding a cock , huge and girthy, the massive white prick spreading her open. The txt messages indicated that the friend then put in a dvd, and that is when the daughters mind snapped. On the DVD was this girl, riding the cock, and the voice was his own. According to the txt messages, as the friend whispered that he got her into fucking on meth, his daughter heard him cry out her name on the DVD. Realizing it was to late to lie. He walked into the bathroom, opened the shower, pulled her out of it and put the meth pipe in her mouth. Without asking any questions she took 4 long hits, dropped to her knees, and became the girl he raised her to be.