It pays to listen to your best friend. And in this case, man’s best friend was also the baby’s best buddy.

After moving to Charleston, South Carolina last year, Benjamin and Hope Jordan hired Alexis Khan, 22, to babysit their then-two-month-old son Finn. Even though Khan’s background check came up clean, their dog Killian still had reservations. When their dog began to act aggressively towards Khan, they became concerned that Killian knew something they didn’t. In order to figure out what was going on, they hid a phone to take an audio recording.

They could hear her cursing at Finn when he cried, and the distress cry turned into a pain cry after a slapping noise.

Thanks to the alert of the family dog, and the clever use of a smart phone, Khan had no choice but to confess to the abuse.

“To know that five months I had handed my child to a monster, not knowing what was going on in my house for that day,” Jordan said. “Had our dog not alerted us to the trouble, had my wife’s instincts not said we need to make something happen, it could have been Finn that was killed by the babysitter. You never know.”

Khan was sentenced to 1-3 years in prison. Additionally, she is now registered as a child abuser database that will ensure she can no longer work with children.