What was initially suspected of being the accidental death of popular teen Dean Shield, who was found unresponsive in a Rutherford drain on Saturday night, has turned into a major investigation as detectives work on whether it is connected with the 18-year-old experimenting with a form of synthetic cannabis.

Dean’s body was found by a resident several hours after he is believed to have bought and taken some of the controversial substance.

And as detectives continued trying to source the origin of the synthetic cannabis on Sunday, emergency services were called to a Telarah residence after two more youths fell ill.

Although their symptoms had been described as grave, police reported on Sunday night that they had been stabilised and were now not considering life-threatening.

Police said all three are believed to have consumed the synthetic drug “Chronic” and it was unknown on Sunday night whether it was linked to the notorious “Kronic” synthetic drug which made headlines years ago.

Central Hunter crime manager Detective Inspector Mitch Dubojski warned other youths who may also have possession of the drug to throw it away.

“Anyone using any form of drugs is putting themselves at extreme peril,’’ Detective Inspector Dubojski said.

The cause of Dean’s death will not be known until at least an autopsy is done, possibly on Tuesday, although toxicology results could take much longer.

But police are concerned that the ingesting of some form of synthetic cannabis was directly relating to his death.

Well known brands of synthetic cannabis were outlawed in 2013 following a series of deaths, including at least two in the Hunter.

However, there have been ongoing concerns that manufacturers were sidestepping the legislation by making subtle changes to the drug’s chemical compounds to they differed from those on the banned list.

There has also been ongoing anecdotal evidence that some of the more popular synthetic drugs, such as “Kronic”, were still being sold on a burgeoning black market.

The teen’s body was only discovered early Saturday evening when resident Dave Pettit decided to mow down a laneway off Bairds Close because the undergrowth was getting thick.

It is unknown how long he had been there for.

“My mower hit the edge of a drain in the lane way - then I saw an arm sticking out,” Mr Pettit said.

“I was shocked - I couldn't believe what I was looking at.

“So I moved closer and saw a man lying face up in the grass.

“I was hoping it was somebody who might just be lying there drunk.

“I shook him and tried to wake him up.

“He didn't move and I had a pretty good idea he was dead.

“Then I just rang triple 0 and waited for police.”

Mr Pettit said he could see no injuries on the body and no signs of blood.

“I did hear one police officer say there appeared to be nothing suspicious about this,’’ Mr Pettit said.

“But it is really sad to know somebody so young has apparently died by themselves out here.

“We don't know if he was alone or with someone.

“But a lot of people do come past here on their way to and from the local pub.”

Dean’s family were too distraught to talk about his death on Sunday, although a friend did write that he was a ‘‘good kid who could do anything when he put his mind to it’’.

‘‘Honestly, there was never a dull moment when he was around,’’ the friend told the Newcastle Herald.

‘‘His laugh was contagious and our lives are never going to be the same without his cheeky presence.’’

Detectives had been called out on Saturday night following the discovery and quickly determined the death was not suspicious, which remains the case.

Originally published as One dead, two fall ill following bad synthetic cannabis batch by Newcastle Herald.