A 14-year-old girl had an empty pint glass held to her throat before being robbed of her mobile phone.
The street robbery took place between 8pm and 8.30pm on Sunday, June 30 as the teenager was walking along Chancery Road, Chorley.
She was approached by a man as she neared the ginnel near Studfold in Astley Village.
The man was carrying an empty pint glass and demanded the girl’s mobile phone.
She initially refused, at which point the man raised the pint glass to the girl’s throat.
The teenager gave him her phone before she alerted a couple walking their dog nearby.
All three of them followed the man past The Baron’s Rest pub, where another man sat outside the pub also tried to help before the man with the pint glass ran off into Astley Park and out of sight.
The man is described as white, around 5ft 10in tall, of skinny build, in his mid to late 20s with short, dark hair.
He was wearing "beatbox" style headphones, a grey, long-sleeved, hooded top and knee length shorts.
He had missing and rotten teeth, a dark tattoo on his right calf and was carrying an empty pint glass.
Detective Constable Gemma Lashley said: “The teenager is still very much in shock and the incident has left her feeling nervous. We need to find the man responsible and I would urge anyone with any information to come forward.
“We have spoken to the couple with the dog who initially helped the girl, but we are also keen to speak with the man who was sat outside The Baron’s Rest who also kindly intervened. If this was you please get in touch with us.”
Anybody with any information can contact police on 101.