A Perth teenager suspected of possessing drugs in Bali has spent his first full night in a Kuta police cell.

Police suspect it is cocaine.

Footage of Mr Murphy’s arrest shows the distraught teenager denying the powder belongs to him.

The police head of Criminal Investigation in Kuta, Ario Seno Wimoko, said Mr Murphy, 18, was still considered “under investigation”.

“We have not yet dubbed him as a perpetrator. We suspect him to be one because we found a suspicious substance on him.”

“He said he bought the substance from somebody and we need to investigate who this person is but for that we need to wait until he is named as a suspect.”

Jamie Murphy at the police station in Kuta, Bali. Photo: ABC News/Adam Harvey.

Under Indonesia’s complex criminal laws, police have two more days to name Mr Murphy as a suspect, which will effectively mean he has been formally charged and will face trial.

They have taken blood and urine samples and they will also test the drugs — if any of those results comes back positive, the teenager faces jail time.

Convictions for possessing even a small amount of drugs in Indonesia can lead to prison terms of one year or more.

Last year a 26-year-old Australian man was jailed for 12 months for possessing one joint of cannabis, and in 2011 a 14-year-old Australian boy spent two months in detention after he was caught with a small amount of hashish.

Murphy could be charged even if substance not drugs

Mr Wimoko said the teenager could be charged even if the white powder turned out not to be drugs. Tourists in Bali are regularly sold substances that purport to be drugs and turn out to be something completely inert.

“If the urine sample is positive we possibly won’t pursue either,” he said.

“We will tell his family through the consulate that the child is a user because he may have used the drugs back in Australia — we can’t tell for sure.”

The teenager’s friends have already visited him in detention, and it’s believed Mr Murphy’s family will arrive in Bali today.

The head of Perth’s Bayswater City Soccer Club, where Mr Murphy is a member, said he was shocked to hear of his arrest — he described it as “very tragic”.

“I spoke to his mother earlier on, she was overwhelmed with the whole deal, and of course she’s in tears as any mother would be.”

He said Mr Murphy was a “wonderful young man. A wonderful athlete, a very promising athlete in our sport. I hadn’t even seen him with a bottle of beer in his hand”.

If Mr Murphy is named a suspect by Indonesian police, he will eventually be moved to a prison cell ahead of a full prosecution.

– ABC