A schoolboy was left with a head injury after being pelted with an egg on Mischief Night.
Lancashire Polic e responded to the incident in Skelmersdale on Saturday night, which left an 11-year-old boy with a head injury.
It came after the force issued a warning to parents to know where there children are ahead of Halloween.
READ MORE: Forensic tent erected at murder scene after man stabbed to death
Posting on the Skelmersdale police Facebook page, a police spokesperson said: "Our staff are just with an 11 year old boy who has a head injury following someone throwing an egg at him.
"This is not mischief, it is a criminal assault and will be dealt with as such."
In a warning to parents, police said: "Do you know where your child is tonight?
"We’d like to appeal to parents – do you know where your children are? With the message to stay safe and enjoy Halloween responsibly.
"The consequences of antisocial behaviour and criminality can have a lasting impact on a young person’s life and on those affected by their actions."
Receive newsletters with the latest news, sport and what's on updates from the Liverpool ECHO by signing up here.
