POLICE have found a missing boy alive, hours after the body of two teenagers were pulled from the Swan River in Maylands.

The teenager was the third person who went missing from a group of five who were being chased by police on Monday afternoon.

Police issued a statement at 2.20pm which said the boy was now with family members.

More details have been released about the police incident that led to the deaths, after the body of a second boy was retrieved this morning.

Two were rescued on Monday afternoon.

Police confirmed the body of a second boy was pulled out of the Swan River at about 9.50am on Tuesday, close to where the first boy’s body was found.

The first body was recovered from the water in Maylands at about 8.30pm on Monday.

Camera Icon Police search near the river in Bayswater this morning after a body was recovered overnight. Credit: Ian Munro The West Australian

On Monday, police were called to Maylands at about 3.15pm following reports several young people were jumping fences near Tranby and Clarkson Roads.

While being chased by officers, at least four of the boys ran into the nearby Swan River.

Two of the boys were rescued close to the banks of the river, but on opposite sides. They have since been reunited with their carers.

No details about any of the boys were being released, at the request of the families, except that all five are under 18 years of age.

Mr Dawson said no charges have been laid against the boys and the incident that led to the police operation have been put aside.

Mr Dawson said two officers responded to the initial incident and they were joined by several Tactical Response Group officers who happened to be nearby.

State Emergency Service volunteers will join an extensive land and water operation on Tuesday morning, which includes mounted officers and police planes.

Officers from the major crime division and the internal affairs unit are investigating the deaths.

Mr Dawson said the fatalities will be treated as deaths in police presence and the coroner will also launch an investigation.

He urged any member of the public with dashcam or other video footage from between 3.15pm and 3.30pm on Monday to contact police.