Police found the boy, believed to be 11 years old, and a man injured at a property in Upminster. Officers arrived to find the boy at about 21:30 BST. The victims were found at a house in Kerry Drive, Upminster.
The man, thought to be in his 40s, had cuts to his head but it unclear what had caused his injuries.
The condition of the man and the boy is not known at present.
A number of people reportedly fled the scene before officers arrived.
No arrests have been made and police are appealing for any witnesses to contact them.
Their conditions are not known, Scotland Yard has said.
Police said: “A number of suspects had made off prior to the arrival of police.
“A police helicopter assisted officers in searches, however there has been no arrest at this stage.
“Enquiries are underway to establish the full circumstances.”
Anyone who witnessed the incident or who has information that can assist the police are asked to call 101 quoting ref 7285/01may.
This comes after Police responded to a separate incident in Central London yesterday.
Tower Bridge was closed as police responded to an incident involving a “suspicious package”.
Traffic and pedestrians were kept away from the central London crossing, with police taping off the entrance to the bridge.
The bridge was later reopened after being closed for an hour.
Police said the package was found to be “non suspicious”.
More to follow…
Published at Sat, 02 May 2020 00:44:00 +0000