Man robbed as 'lonely heart' ad goes wrong

Detectives in two states are hunting for a NSW man accused of robbing a stranger at knifepoint after selecting his victim through a lonely heart advertisement.

It is another example of social media and peer-to-peer applications being used to aid crime.

Beau Robert Bartlett responded to an advertisement through online classifieds site Craigslist in December.

Police believe the man who posted the ad on Craigslist - more commonly used to sell furniture and find flatmates - had been seeking "male companionship".

Bartlett allegedly arranged to meet the man outside his home in Liverpool in Sydney's west. He allegedly held the man at knifepoint and ransacked his unit, getting away with personal documents.

"It appears the whole meeting had been allegedly set up for the purpose of an armed robbery," Detective Sergeant Graham Hibbs said.

Bartlett has no fixed abode and police believe he may be moving between NSW and Queensland.

There is a warrant out for his arrest.

The exploitation of dating applications has been linked to recent high-profile crimes, including the alleged murder of a woman on the Gold Coast last year by a man she met on Tinder.

Chat applications, such as WhatsApp and WeChat also present a challenge to police as criminals turn to the technology to lower their chances of detection.

A NSW Police spokesperson said peer-to-peer applications evaded the scrutiny of more public platforms including Facebook and Twitter.

"Police certainly have concerns that a range of criminals including drug dealers and pedophiles are operating in that space and taking advantage of that hidden communication," the spokesperson said.

Detective Acting Inspector Paul Grace said there have been several cases in recent years linked to dating and chat apps and sites being exploited, including a man who was robbed at gunpoint by two men he arranged to meet through Skout.

The offenders were sentenced to four years' jail.

Det Sgt Hibbs said people using the internet to set up romantic encounters or other meetings needed to tread with caution.

"You don't know who you are meeting or if the other person's intentions are as genuine as your own," he said.