A nanny in the U.S. has been fired after she was caught on camera appearing to hit and swear at the children in her care.

Shalin Cruz, a Colorado mother, hired a nanny to take care of her two children, including her six-year-old son, who she says has autism and Sensory Processing Disorder.

Cruz installed a hidden security camera in the house after she says her son came to her and said that he was being hit in “a way [she] wouldn’t like,” and a neighbour tipped her off that shouting was being heard from her apartment during the day.

Cruz says in a Facebook post that what she found was “every parents [sic] nightmare.”

In one video Cruz posted, the nanny can be seen roughly pulling one child from his seat and apparently hitting him as he cries.

“You better shut your mouth,” the nanny tells the crying child. “You’re about to get your ass whooped.”

In another, she pulls out a wooden spoon to hit a child, before sending him away crying.

“Go to the bathroom, I don’t want to hear it,” she says.

Cruz told KDVR, a local station, that she tried reporting the incident to police, only to be told that the actions don’t reach the threshold for criminal charges.

Castle Rock Police Department’s Public Information Officer Joseph Cybert told CTVNews.ca that there are numerous factors that go into play when determining when physical discipline becomes abuse.

“If there’s bruising, if there’s lacerations, something to that extent, that triggers a full investigation into potential criminal charges,” Cybert said.

An officer responded to Cruz’s call and reviewed the case with her before determining that it didn’t meet the criteria to proceed with an investigation.

Cybert says that because of the attention the case has received, the department’s investigations unit will undertake a full review of the case to ensure that nothing was missed.

“Preliminarily, it doesn’t look like there was anything missed in the initial report,” Cybert said. “But any time a child is involved in a case, I want to make sure we’ve looked at every possible angle and make sure this thing is exhausted before it’s closed out.”