A 19-year-old Utah man has been charged with raping a 16-year-old girl he met after randomly contacting her father as part of the online text-your-number-neighbor challenge.

Issac Francisco Alonso of Gunnison was charged in Sixth District Court with rape, a first-degree felony; and obstruction of justice, a second-degree felony.

The challenge, which trended on Twitter this summer, involves texting your “number neighbor” — texting the first nine digits of your cell phone number, and then adding or subtracting one from the final digit.

According to a probable cause statement, Alonso sent a text to the girl’s father, and asked his daughter to explain the number-neighbor challenge. The father learned that Alonso lived nearby and that they had friends in common. The girl told police she continued to text Alonso on her father’s phone, and then texted and spoke with him on her phone and communicated via Snapchat. The girl also told police Alonso asked her for nude pictures of herself and she refused.

On Aug. 8, the girl agreed to meet Alonso at a local convenience store. She told police she got in his car and he drove her to an area east of Ephraim known as Black Hills, where he parked and started kissing her. She told him to stop and texted a friend: “Call me, I think I'm about to get raped.”

According to the police report, Alonso took away the girl's phone and “forcefully” pulled her into the back seat of the car, removed her clothes and raped her, “holding her down with his hands on her neck” as she resisted.

He then drove her home, “trying to make small talk” along the way. The girl said she asked Alonso, “How many people have you done this to?” He replied, “Don’t ask questions you don’t want answers to.”

According to the girl’s father, she was “very upset and crying” when she returned home, and “she looked like she had choke marks on her neck.” The father called Alonso and asked, “What did you do to my daughter?” Alonso replied, “Nothing, why?” He then asked to speak to the girl privately. The father refused; on speaker phone, Alonso “tried convincing her that what had happened was consensual.”

Police obtained a warrant to seize Alonso’s car and phone; he claimed he didn’t have a phone, but it was located in his home.