When I was around 15, my mom started dating this guy named Dan. The first time I met Dan, I didn't really like him. I couldn't really put my finger on the reason why. I'd like to say that the hair on the back of my neck stood up or something foreboding like that, but that's not the truth. I just didn't like him. But since I couldn't put my finger on the reason why, I ignored my personal feelings and was always polite when I saw him.
After a few months of him dating my mom and hanging around all the time, I started to get the feeling that Dan didn't really like me, either. He always teased me about really stupid shit, and especially about me having my first boyfriend. And it wasn't the "Haha, I'm just messing with you" type of teasing. It always sounded like there was a hint of malice in it. Nobody else seemed to notice it, so I just ignored him.
But the weirdest thing Dan liked to do is almost hard to explain. He would take things that he overheard me say or saw me do, and run to my mom and tell her, but he would put some creepy, sexual twist on my words/actions, which my mother would later confront me about. For example, one night around the holidays we all went gift shopping at the mall. This was before every teenager had a cell phone, so my mom just told me to meet her and Dan in the food court in an hour, and we parted ways. An hour passes and I head to the food court to find them, only I don't see them anywhere. So I sit down and wait for them. After a while I start to get impatient, so I scan the food court again, and I see a friend from school, Ray. I walk over to Ray and we start chatting. I mention why I'm waiting and he offers me his phone to call my mom. I'm about to dial her number when I hear a man shout my name. I look up, and it's Dan. He walks up to me, glares at Ray, and tells me that he and my mom have been looking all over for me. He motions for me to follow him, so I thank Ray and tag along. We get back to my mom (they had been sitting at a tiny table jammed in the corner that I couldn't see) and she asks "Where were you?" Before I can even answer, Dan practically sneers at me. "I found her, she was hanging all over some guy." "No, I wasn't" I say incredulously. "A friend let me use his phone and I was about to call you guy." Dan tells me to "save it."
Another time, my mom asked Dan if he could help me practice driving for my Driver's Ed log. He took me to his work parking lot to work on parallel parking, and as we were circling the lot he pointed out a nice two-door sports car. Trying to make conversation, I told him that some rich kid at my school received that same car for his 16th birthday and was showing it off to everyone after school. Dan asked me if I got a good look at the interior, and I said "Yeah, it's really nice inside, but the back seat is really cramped." I find out later that Dan told my mom I told him that I "fucked a kid from school in the backseat of his new sports car". Classic Dan.
My mom started to get the hint that Dan and I didn't really get along, so she started spending time at his place instead of bringing him to ours. My mom later told me that's when she noticed Dan was kind of weird, specifically with his computer. My mom asked him if she could use it to check her email, and Dan absolutely refused. When my mom asked him why, he wouldn't give her an answer. If she stayed at his place while he was gone, he always made sure he was logged off before he left.
Well, one fateful day he was late for work and because he was in a rush, he totally forgot to log out. Of course the curiosity was killing my mom, so as soon as she heard his car pull away, she got right on the computer and started snooping. She didn't have to look for long, because saved right to his taskbar were all of these links to porn videos. Laughing, my mom thought "Is this all he's worried about? It's porn! What guy doesn't watch porn?". They had watched porn together before (fucking gross, mom), so why did he feel the need to hide this stuff? She starts watching one of them for shits and giggles, only to discover that it was some really young girl, and the video was definitely "amateur style". Now even my mom knows that there's fetish porn that has to do with younger-looking chicks, but she told me that this girl was young. Like, almost pre-teen young. But what really weirded her out was the amateur style that the video was shot in, like it was recorded on someone's shitty cell phone, and not some at least moderate production-value studio porn. She clicked on some other saved links, and they all contained pretty much the same shit, some low-quality video of some very young-looking girl. Others were dead links.
My mom confronted Dan about it when he got home from work that night, and he lost his shit on her. He told her to get the fuck out, and my mom happily obliged. She told me she left an anonymous tip to the police about it, but wasn't sure if anything ever became of it. After all, it could have just been some poorly-filmed teen fetish porn or something, although my mom feels that's unlikely. She said she was mainly concerned with having Dan around her teen daughter (and her pre-teen daughter, my sister) if he was into stuff like that, as the notion made her uncomfortable.
TL;DR mom's boyfriend was into some sketchy porn