Parents are highly advised to familiarize themselves with Kik free texting app that police had dubbed as ''the No.1 social media problem involving teenagers".

Kik app was reportedly used by 50 million people. This made teenagers prone to connect with strangers. The app was designed for 17 -year-olds and older teens but a lot of children ages 11-15 were also using the app.

Kik had been associated with the proliferation of "sexting" among teens, especially with those who were posting their photos publicly and inviting strangers to "Kik me" privately through chat.

''They're literally promoting themselves, saying, 'Come and talk to me'. They can randomly chat with somebody and send images, and they don't understand the consequences of who is using that information," Cyber safety expert Ross Bark told The Sydney Morning Herald.

''It's hidden to most parents. Young people may not even know who they are communicating with. No one is using their real names and that's a problem ... social media is very agile. Criminals move from platform to platform where they feel their chances of being detected can be reduced," NSW Police Force social media spokesman Strath Gordon said.

Kik app was where the 14-year-old Krystal Muhieddine met the 17-year-old boy from Sydney whom she had run away with. After a few chats through Kik, Krystal met with the boy to watch a movie with him without telling her parents.

During their second meeting, Krystal and the boy decided to sleep out in a tent bringing with themselves Nutella, tuna and pizzas. It was supposed to be an innocent thing as they cooked spaghetti on a fire and had fun. However, her parents did not know she was out in late hours.

''He had money, we went to the shops and got some food ... We toasted marshmallows. I had never had them like that. We were kind of just clearing our heads, there wasn't really much going on just lying down and doing nothing. Walking on the trails.''

Krystal admitted to SMH that she was afraid of what she did. She was scared of her parents when it dawned on her that what she did was totally wrong and a valid reason for panic.

''Of course. I was a bit scared to kind of turn on my phone. I was just waiting for when I was ready to call them. I missed everyone. I knew they were probably going through a hard time. I wasn't thinking straight. I was stressed from school and work and then just got oversensitive about everything. In my own little head I was making excuses to get mad to make myself feel better.I was upset and I made a decision based on my anger. I should have thought it through more and talked to my parents.''