A teenager who jumped into a canal while fleeing from police did not look in difficulty and had refused help before he drowned, officers have told his inquest.

Jack Susianta, 17, was chased by police in the midst of an ecstasy-fuelled breakdown, and jumped into the river because “he had nowhere else to go”, according to a witness at an inquest into his death at St Pancras Coroner’s Court.

Since last Monday jurors have heard how Jack returned from festival Secret Garden Party in July last year “over emotional”, “nervous and agitated” after taking MDMA daily while there.

Two days later during a psychotic episode, he “karate kicked” a hole in a window and fled his home in Thornby Road, Lower Clapton, wearing just his socks, T-shirt and boxer shorts.

His mother Anna Susianta called police who chased him as he ran into the River Lea near the Kingshead Bridge in Lea Bridge Road, Walthamstow.

Hackney Gazette: Tributes at the scene where Jack drownedTributes at the scene where Jack drowned (Image: Archant)

The teenager’s mental state meant he feared the police were not the real police, the jury has heard.

Pc Tom Griffiths said he saw Jack Susianta go underwater and believed it had been a “deliberate act” in an attempt to evade him and his fellow officers.

Describing the moment Jack drowned, he added: “He did not thrash down. He really slowly sank down, it looked like he was trying to go underwater.

“I thought maybe he was going to swim down river.

“I saw him in the water, he was treading water and he did go under a couple of times. To me it looked like he was going down to swim underwater - it looked like a deliberate act.

“He did that a couple of times but he did not look like he was in difficulty at any point.”

A buoyancy ring was thrown to the teenager but he swam away from it, the constable said.

His colleague Pc Richard Hughes, who described himself as being unable to swim the length of a pool, said he assessed the risk of trying to save Jack as “too dangerous”.

He added: “I thought if dived in the water and got near to him - he did not want to be rescued.

“I thought he might have tried to fight us off in the water.”

He also denied claims the search operation was uncoordinated.

Suggestions that officers should have tried other methods to rescue the teenager, such as forming a human chain, may have been considered but there were risks.

“Just because we did not do them does not mean we did not consider them,” he said.

“It’s our job to consider these contingencies - members of the public don’t think about these contingencies because there’s an emotional response.”

Witnesses have claimed police refused to enter the water to save him but the Metropolitan Police have denied this, saying one officer risked his life and entered the water.

The inquest continues.