Nona Belomesoff, 18, was found dead in a creek south west of Sydney after going to meet a Facebook 'friend'.
Christopher Dannewig, 20, allegedly set up a bogus profile to pose as an animal rescue worker and enticed his victim to the isolated spot.
Nona, who is described as a animal lover, was told she first had to go on an overnight camping trip that would be part of her initial training for the post.
Murder charges: Nona Belomesoff, left, was found dead in a creek south west of Sydney, after she allegedly met Christopher Dannveig, right, pictured on his Facebook page, who had promised her a job
Filled with excitement, she headed off to a railway station to meet 'Jason Green' - the fake identity allegedly set up by Dannewig.
The teenager told her family, who also believed the offer was genuine. Her body was found on Friday night after she failed to return home.
Dannewig, who also has profiles on My Space and Bebo, was charged with murder yesterday and was refused bail after appearing in court.
Police issued a fresh warning to parents to monitor their children's internet habits.
Homicide Squad detective inspector Russell Oxford warned about the dangers of Facebook and other social networking sites.
'It's an area where predators and perverts and other people just get onto. You just don't know who you could be talking to,' he said.
'This young woman had a passion for animals and was led to believe the overnight camping trip would lead to a potential job with an animal welfare group,' Inspector Oxford said.
'She told her family and they thought it was a genuine training area she was going to. That was part of the story to encourage her to go out there.
'And it wasn't until later on that we found out there is no such training facility like that and the people aren't affiliated with that place, so it was a bogus ruse to get her out there.'
Nearly 30 police officers searched bushland before the teenager's body was found in the Campbelltown creek, although her cause of death has not been revealed.
Inspector Oxford said: 'It is heart-wrenching. We have all got kids that age. I have kids that age myself.
'I have been doing this for a long time, but we're very upset. To go outside in the dark and find a young girl lying in the creek bed...'
Comments her accused killer, Christopher Dannevig, wrote on social networking sites hinted at a troubled life.
'Life is full of s*** sometimes,' he wrote earlier this month. In April he wrote that 'a broken heart will heal in time but some wounds won't'.
Nona Belomesoff's grief-stricken mother, Nina, said through her tears today: 'She was scared she was going to lose the job she really likes, so she went - and never came back.'
Her brother Gary, warning young people not to trust strangers they meet over the internet, told Sydney's Channel Seven News: 'I can't believe such a human being would do this. It's so cold hearted.
'Be careful - you can't just trust anybody over the internet.'
Dannevig, who appeared before Parramatta Court, west of Sydney, via a video link from prison at the weekend, has been remanded in custody and will appear in court again on Thursday.
