When I was in high school, I was hospitalized a couple times for my depression. One of the other patients in the ward was a guy in his mid-twenties who apparently took interest in me. I was released, and went back to school and work. I worked at the gas station directly across the road from the hospital.
A few weeks later, he was released as well, and happened to see me at work. He started coming in several times a day, asking my co-workers for my work schedule. When they refused to give it to him, he lied and said he was my fiance, hoping that would change their minds. He also went around to lots of other local businesses- where a few of my friends worked- and told them that we were engaged as well.
His father was a regular customer who often came in during my shifts. One day, he (the guy's father) called the store and asked to speak to me. During that conversation, he told me that the reason his son had been hospitalized was because he'd sexually assaulted 3 women. He then warned me to avoid his son, and call the police if he showed up again, and have someone walk me to my car after work each day.
Later that week, the son came back in. Luckily, I was in the back, so he didn't see me. My manager told him that I'd gone out to run some errands and would be gone for two hours, hoping he'd be discouraged and leave. Instead, he said he would wait. She then told him that he needed to leave or she would call the police.
I eventually quit that job and stopped going down to that part of the county because I felt so uncomfortable there, not sure if he was nearby. I haven't heard from him or his father since, but I hope he's in jail where he can't stalk/scare/hurt anyone else.