[Actionable solutions] I will only speak for myself in this case, but I found whenever I stood up to this one harasser about a specific thing that made me uncomfortable, he would switch gears and apply a different tack – like calling me by a weird nickname for a month instead. If you can’t pull the aggressor out of the situation then someone needs to clearly explain to him/her that a file has been opened and he/she are being observed. [I felt …] 
Anxious feelings of possible retribution