Detectives have launched a manhunt after a suspected “corrosive substance” was thrown at two boys at a London Tube station.
The pair report having the substance thrown at them at Elm Park underground station just after 8pm on Saturday.
They were taken to hospital but their injuries are not believed to be life-threatening or life-changing.
Officers have released CCTV images of three people who they believe may have information that could help their investigation.
Investigating officer Detective Inspector Marvin Bruno said: "Violence in any form will not be tolerated on the rail network and we would like to reassure the travelling public that our officers are working tirelessly to identify and apprehend those responsible.
"We are really keen to speak to the people in the images, or anyone else who witnessed the incident, as we believe they have information which could help our investigation. If you know them or have any information that might help, please get in touch."
Last month a mother-of-two was doused with a corrosive chemical in a harrowing attack on her and her young children in Clapham.
Police believe Abdul Ezedi, who was from the Newcastle area, threw a chemical over his former girlfriend in the attack on her and her young children, aged eight and three.
During a manhunt for Ezedi investigators pieced together CCTV footage to establish that he had entered the River Thames. His body was recovered last week and he died from drowning, Metropolitan Police confirmed.
The mother who was attacked is now in a stable condition and no longer sedated, the police have said.
