POLICE are investigating whether synthetic cannabis linked to a teenager’s death and two other men being admitted to hospital was bought at a tobacco shop.

Detectives executed a search warrant at a shopping centre tobacconist in Rutherford in the Hunter Valley yesterday after 17-year-old Dean Shield was found dead in a back laneway less than 1km away on Saturday night.

media_camera Dean Shield, 17, who died from suspected synthetic cannabis overdose.

Police believe he smoked synthetic cannabis earlier in the evening. Two other men, aged in their early 20s, were rushed to hospital on Sunday after smoking what is ­believed to be the same substance in the nearby suburb of Telarah.

Staff at the shop denied selling the synthetic cannabis when approached by The Daily Telegraph, and a security guard then refused to allow them to be questioned further.

A tenant in a rental property also searched by police admitted he had provided the synthetic cannabis to one of Dean’s friends. But the man, who asked to be known only as Shane, said he didn’t realise it was illegal because he bought it regularly from the tobacconist as a “herbal high”, paying $60 for 3g.

media_camera Dean Shield was found dead near a drain.

Another man at the house said it was sold at the shop as “Bangkok Betty” — the same brand of synthetic cannabis believed responsible for causing brain damage to a Hunter Valley man last year.

Synthetic cannabis was outlawed in NSW in 2013, but it is still sold through some retail channels as “herbal tea” or “pot pourri”.

A friend of the two men taken to hospital on Sunday night said the pair smoked what looked like cannabis. Shortly after, both started convulsing dramatically.

“I’ve seen some bad shit in my time but nothing like that,” he said.

“It was horrific.”