Fifth Boy Found Following Swan River Police Chase

It comes after two bodies were pulled from Swan River by WA Police.

Two teenage boys have died after jumping into Perth's Swan River following a police chase Monday afternoon.

Two others were found alive after four of the boys entered the water to avoid officers, before the fifth teenager was located alive on Tuesday afternoon.

Police declined to reveal the identities or ages of the deceased, but confirmed all boys involved are believed to be teenagers under the age of 18.

The second boy's body was pulled from the river at about 9.45am Tuesday, some nine hours after the first boy's body was recovered.

Police described the deaths as a "nothing short of a tragedy."

The body of a second teenager has been recovered from Perth's Swan River while the search continues for other teens after they jumped into the water to avoid police. (AAP Image/Richard Wainwright)

"My condolences and the condolences of all police to the families of the two deceased boys and the friends," WA Police Commissioner Chris Dawson told reporters Tuesday.

The tragedy unfolded after police responded to reports of teenagers jumping fences in Maylands, north east of Perth's CBD, on Monday afternoon.

A foot chase ensued, and a group of five teenage boys fled on foot -- four then jumped into the Swan River to avoid officers at about 3.15pm.

Two of the teens got into trouble in the middle of the river. Their bodies have now been recovered. Another two teenagers were taken safely into custody.

The fifth teenager, who had last been seen running on the foreshore on the Maylands side of the river, was located alive on Tuesday and reunited with his family.

"There was an extensive police search, which began midafternoon yesterday, when we believe five teenage boys were involved, four of whom entered the Swan River," Dawson said.

"Police responded at the scene and were able to safely recover two boys from the river. Two boys were believed to have got into difficulties in the middle of the river, and succumbed to the conditions and were not seen to resurface."

Search and rescue personnel assist in the search for missing teenagers in the Swan river in Maylands, Perth, Tuesday, September 11, 2018.  (AAP Image/Richard Wainwright)

The deaths are being treated as "deaths in police presence," but Dawson said the boys who died never came into physical contact with officers.

The two boys who were taken into  custody were treated by paramedics and given warm clothing before speaking to police.  They were returned to their families overnight without charge.

"We are not gonna be, at this stage, dealing with criminal charges," Dawson said.

The matter will be referred to the State Coroner.