I think I might be living with a serial killer

I've lived with my current boyfriend for 2 months now, he's been amazing the entire time. I even introduced him to my parents and they loved him. <br><br>The weirdness started about a month ago, when I was home alone. I was sitting on the couch at 10:30 when I heard really loud footsteps on the second floor. I hear the footsteps, then I hear the heavy footsteps stop. I hear nothing else. It was so strange that I went upstairs to check it out. Everything was normal. I went back downstairs and sat back on the couch and waited. Nothing else happened. <br><br>A couple days later this happened again. This time, I heard heavy footsteps and the shower turn on. I went to check out the noises and the bathroom door was locked from the other side. I stood there for a while, and I could hear him moving around in there. I finally left and went to bed. <br><br>This happened a couple more times, and it's always at night. The first few times, I checked to make sure the doors and windows were locked. Each time I checked, everything was. I also checked the security cameras and nothing was out of the ordinary. <br><br>I've been really freaked out, but I didn't say anything to him about it because I don't want to accuse him of anything without evidence. <br><br>Tonight, I was home alone at 10:30 again when I heard the footsteps upstairs. This time they were really heavy and it sounded like someone was running. I went upstairs to check it out and the front door was wide open. The back door was still locked. I checked the back patio and nothing was there. <br><br>I'm scared. I don't know what else to do. I've been really lucky so far, but something bad could happen anytime.<br><br>TLDR: I've been hearing strange noises at night while I'm home alone with my boyfriend. The first time I checked and nothing was out of place. I don't know what to do.