Police are hunting two suspects after an harmful substance was thrown in the faces of two boys in Harlow.
The incident took place at around 3pm on January 23, when the two youngsters, aged 14 and 16, were walking through an underpass in The Hides.
Someone threw a substance into their faces, causing reddening and swelling to their faces and eyes.
Officers would like to speak to two men in connection with the incident.
The first is described as Asian, around 17 years-old, 5ft 5ins tall, of slim build and wearing grey tracksuit trousers and black shoes.
The second is described as white, in his late teens to early 20s, around 5ft 6ins tall, of athletic build with black hair and stubble, wearing a white t-shirt and dark trousers.
Anyone with any information is asked to contact DC Lauren Strangward at Harlow Police Station on 101 or Crimestoppers anonymously on: 0800 555 111.