Miller insisted she never forced the dog into any sexual act and she engages in the activity whenever there was a family in the house.
Ashely Miller has reportedly admitted to taking selfies while she was having sex with a dog in her grandmother's house.
The teenager told police how she coaxed her pet dog, a pit bull called 2-face, into performing a sex act on her between 30 and 40 times over the past five years.
Officers have also indicated she admitted to making her previous dog, a pit bull-Rottweiler cross named Scarface, perform oral sex on her.
Miller, from Bradenton, Florida, has been charged with two counts of sexual activities involving animals after police discovered the vile images on her mobile phone.
Ashley narrated that, whenever she wanted to have sex with the dog, she would lock herself in a bedroom, take off her underwear and beckon the dog over.
Miller told the officers that less than 10 of the acts occurred after she turned 18 in February.
On at least two occasions, she took selfies. The 'puppy porn' pictures were discovered in two hidden folders on Miller's phone, one titled "2-face fun" and another titled "Me", police said. A veterinary doctor has indicated that 2-face showed no sign of injury when she checked her out.
Miller is due to appear in court next month.