Earlier today, Slenderman sent out Masky to go explore an abandoned building somewhere in the forest, because teenagers had been there. While he was there, he randomly FaceTimed Hoody. He answered, holding the camera up to fit you and Sally in the frame, who were trying to see why Masky called.

"I think I see something looking at me through that window..." Masky randomly began, pointing the camera at the window. You could faintly see Jeff, but not that well. "I might...be a little...delusional... but I think I see something looking at me through that window." So that's where Jeff had been all day.