An Ohio couple awoke in the middle of the night to the sound of a man screaming "wake up baby!" before realising a hacker had hijacked the wireless baby monitor in their daughter's room.
Heather and Adam Schreck said they felt "violated" after the encounter, and the couple had no way of working out who the online intruder was.
The Cincinnatti couple had stirred during the night, thinking they heard a voice.
Heather checked on their 10-month-old, Emma, by looking at her cellphone, which streams the camera feed from the monitor that sits above the baby's crib.
Heather saw that the camera was moving erratically, when it is only meant to move if following the child or someone else walking about the room.
"About the time I saw it moving, I also heard a voice again start screaming at my daughter," Heather told US TV.
"He was screaming, 'Wake up baby. Wake up baby'. Then just screaming at her trying to wake her up."
Adam bolted to Emma's room, and watched as the camera turned from his daughter and pointed at him.
"He was screaming at me ... so I unplugged the camera," Adam said.
They then realised the camera in the room had been compromised.
"Someone had hacked in from outside," Heather said.
"You do kind of feel violated in a way," Adam said.
IT experts say any internet-connected device in the household can provide an easy way for online intruders to open a cyber door directly into your home.
They suggest change Wi-Fi and camera passwords, ensuring they are both different and checking websites for your technical equipment for updates.