The Silent Caller

One evening, Julia's phone rang with an unknown number. 

She picked it up but all that she heard was silence.

She put the phone down, bewildered, but the phone rang again immediately. 

This time, She hesitated before picking it up.

"Hello?" she said, her voice slightly shaking.

A faint whisper came through, "I see you."

Dumbfounded, Julia cut the line. Then her phone rang again. This time the 

voice was clear. "I know you're alone.

 I'm closer than you think." She locked all doors and windows. 

But the phone rang again, this time she stunned and saw that