The following are incidents that have been brought to my attention by my mother, and some I have seen myself. My mother works at an elementary school in the town of Worth, IL. She's been doing janitorial work there for about 7 years now, and I generally go help her when she's on the night shift. Many times, and only while we're at the very front of the school, have we seen what appears to be a man walk down the hallway and turn the corner. Upon further "investigation", my mother and I found no one else in the entire building. But the incidents haven't stopped there.
Around September of this year my mother was working alone and was turning off all the lights, on her way to sign out and lock up when she heard a very loud whistle, something along the lines of a dog whistle that seemed to come from a man, or seemed to have a man's tone about it. Knowing she was the only person in the school, she re-checked every room to find no one around, and immediately left.
Recently as well, one of the longest standing teachers passed away. Ever since, smaller stranger coincidences have been happening. Posters will fall off walls, desks will be moved, and erasers will be off the ledges, and strangely enough, absolutely nothing will happen to the deceased teacher's old classroom...
My mother and I tried to dismiss the falling posters as the sticky tack used to adhere them becoming old and dry, but when it happens in every single room, even after a humidifier is placed in every room, that's a bit fishy.
Also on the day that the teacher died, I was the first one in my house to receive the news. I was on the phone with an aid who works there, and in the middle of the conversation, she got another phone call and said she had to go because Jane Smith (I will not use her name here in order to keep her identity safe) was on the other line and she'd have to talk to me later.
A few days later, my mother said her "friend" (as we like to call it) had visited her and was moving around chairs in desks. I questioned which student's desk it was and when my mother showed me, it was the daughter of Jane Smith! I've never personally witnessed anything being moved around, nor does it seem to happen while I'm at work with my mother, but I do not doubt my mother's word for an instant. If any of you could have seen her face the night she heard that whistle, as if it was right in her ear, it was of complete and honest fear.
No actual harm has ever come to my mother or me, so we'll continue to watch and see what our Friend gets us into next time.