TULSA COUNTY, Oklahoma - A Green Country mother was shocked when a 25-year-old man sent her 12-year-old daughter a picture of his genitals. She says he did it through an app called Tango that her daughter was using to make video phone calls with her friends.

She wants to warn other parents what can happen.

Twelve-year-old Aleisha, like most kids her age, spends a lot of time on her phone, playing games and talking to friends. She and her friends use the Tango app, to call and see each other on video.

No phone numbers or names show up, just screen names.

Recently, someone called they didn't know and when they answered, they didn't see a face, they saw video of man's private parts.

"It was disgusting. Bad," Aleisha said.

The app also allows you to text, so the girls sent him a message, claiming they were younger than they actually are and telling him not to contact them again.

"She said, 'I don't know you, I'm only 11,' and he said, 'That's great, 25, I love you, sex, xxx,' then tried calling her again."

At first the girls laughed it off, but when he wouldn't stop calling, they got scared and told their moms.

"He wouldn't leave us alone and we thought if we didn't tell our moms, he could find us," Aleisha said.

Stephanie thought only people in your contacts list could call you through Tango. She says she didn't realize, anyone on Tango can see who else is currently using the app within a four-mile radius through the phone's GPS and call them randomly, regardless of age.

Ironically, the same screen name who had called her daughter, called Stephanie the next day through Tango, but again he didn't show his face. She sent him a message.

"I know what you've done, you sent pictures that were inappropriate to my 12-year-old daughter and the police know. He sends me back a boing face, sad face with tears which really irks me because he's like 'oh, I'm so sad, like you'll ever find me.'"

She's deleted Tango off her daughter's phone, and now Aleisha uses the oovoo app to video chat with her friends because you have to accept someone into your contacts before they can call you.

Stephanie filed a police report, and the officers forwarded it to Tulsa's cyber crimes unit. But, she was told it might be tough finding this guy because he went through a third party app, so it's not like tracking him through phone records.

She may never know who he is, but she knows he was within four miles of her daughter when he contacted her.