12/30/2011 01:18 pm ET

Frankie And Kayla Almuina Arrested For Facebook Photos Of Duct Tape-Bound Children (VIDEO)

For the second time in as many weeks, parents have been arrested after allegedly posting pictures on Facebook of their children bound in duct tape. In both instances, the parents told authorities the disturbing photos were nothing more than a joke.

In the latest case, Frankie Almuina, 20, and Kayla Almuina, 19, were arrested Thursday at their home in northern Arizona and charged with two counts of child abuse after police learned the couple had posted to Facebook photos of their two young children bound with duct tape at the mouths, wrists and ankles, Fox News reported.

In one particularly disturbing photo, a child is hanging upside down from exercise equipment, according to authorities at the Coconino County Sheriff's Office in Flagstaff, Arizona, who spoke with Fox News.

"I am shocked and horrified, and I will tell you that in 30 years in law enforcement in Arizona, this is one of the most horrendous things I have ever seen," Commander Rex Gilliland told Fox News affiliate KSAZ-TV.

Perhaps just as unsettling was the couple's claim that the photos were simply a joke.

"They did indicate that they were simply joking, however it is apparent through the photographs that this was not a joke. The photos depicted the children's faces in sheer terror," Gilliland told KSAZ. "Clearly you can't tape another person's hands and mouth shut. Especially small children. It is clearly child abuse and they were charged appropriately."

Apparently that message just isn't clear enough for some parents.

Just two weeks ago, Chicago father Andre Curry, 21, was charged with aggravated domestic battery after allegedly posting photos on Facebook of his daughter bound with blue duct tape around her mouth, wrists and ankles.

The caption on the photo read "This is wut happens wen my baby hits me back," police told the Associated Press.

But Facebook has proved a positive tool for parents as well.

On Dec. 27, CBS News reported that a Salt Lake City mother who had been held captive with her 17-month-old son for five days was rescued after posting a cry for help on Facebook.

The woman and her son were being held hostage by the father of one of the woman's other children, who abused the pair over a period of five days before she was able to hide in a closet with a laptop and make the life-saving post, police reported.

"Facebook was her only outlet that she had at the home," Police Sgt. Jon Arnold said. "It just happened that she was able to use it."