A 7-month-old baby couldn’t tell his parents about his cruel sitter’s abusive behavior. Soon, however, the couple started to receive messages from the family dog. When they did, they discovered a horrible reality.

When Benjamin and Hope Jordan moved to Charleston, South Carolina, they needed a babysitter for their infant son Finn, according to WCSC. After finding what they felt was a good fit at the time, they did their due diligence, going through the safe process of performing a background check. With all seeming good on paper, they decided to hire 21-year-old Alexis Khan, who had held previous babysitting jobs.

After hiring Khan to watch Finn in their home while they worked, the Jordans said everything seemed to be going well. They got along with Khan, who they described as a “personable lady,” but things slowly started to change. About five months into Khan working for the family, the Jordans’ loyal family dog, Killian, seemed to be trying to alert them to a problem.

The black lab and German shepherd mix was usually a docile and friendly dog, but his personality began to change drastically — but only when Alexis Khan came around Finn. “We noticed the dog was getting very defensive when Alexis was around,” Benjamin Jordan recalled, according to ABC News. “He would growl and stand between her and our son. His hair would stand up on the back of his neck and we knew something was up.”

With Killian growling and snarling at the babysitter, Benjamin and Hope couldn’t shake the feeling that something was very wrong. “He was very aggressive towards her and a few times we actually had to physically restrain our dog from going towards her,” Benjamin said, explaining why he and Hope were growing increasingly suspicious that something was wrong.

Feeling increasingly troubled by Killian’s reaction to Khan, Hope suggested they place an iPhone under a living room couch on voice memo in order to record audio while they weren’t home. They expected that they might catch Khan abusing their dog since Killian’s behavior had been out of the ordinary, but they captured something much worse. As Hope played the recording, she heard what she described as a “nightmare.”

“For seven and a half hours, my son cried nearly the entire time. She was cursing at him, calling him horrible names, and the thing about it is, it came for no reason. He wasn’t acting up, he hadn’t been crying until she left him alone in his crib for hours, or, of course, the physical abuse,” Hope said, referring to “slap noises” she and Benjamin heard on the audio.

Listening to the tape left Benjamin horrified as well, wishing he could reach through the device and go back in time. “Shut the f*** up,” Khan could be heard telling 7-month-old Finn and calling the infant expletives as he cried. But, it was the slapping and shaking noises that worried them most.

With those sounds, Finn’s cry changed from a “distressed cry” to a “pain cry,” Benjamin recalled. “I just wanted to reach through the audio tape, go back in time, and just grab him up,” the father explained, wishing he could comfort his son. “We just could not believe it.”

The stunned parents immediately took their baby to the hospital, where doctors found Finn to be in perfect shape but still alerted the police. Initially, authorities were concerned that the audio recording wouldn’t be enough to press charges.

When a Charleston police detective interviewed Alexis Khan, however, she gave a full confession. The South Carolina babysitter pleaded guilty to assault and battery and was later convicted of child abuse. She was sentenced to the maximum three years in prison.

Thanks to Killian’s determination, alerting the boy’s parents that the woman was mistreating their child, Finn was saved from further abuse and other children will also be protected from this monster, parading herself as a childcare provider. Not only was Alexis Khan thrown behind bars, but her name was also placed on a registry of child abusers, preventing her from working with children again.

“Who knows how many children she has abused or how many more she would have had it not been for our dog,” Benjamin Jordan said, grateful that the family pet was more than just a good companion for their son. Killian was Finn’s protector and life-saver, proving once again that not all heroes wear capes. Some have fur and walk on all fours as they sniff out the evil villains among us.