Police have sealed off a section of Fishergate by Waterstones.Advertisement
Bystanders said the pavement outside the book shop was covered in blood.
A police car and officer stood guard at the main shopping streets junction with Glovers Court.
It is understood an incident occurred around 4am on Saturday 28 June, leaving a 30-year-old man in hospital.
Three men from Preston have been arrested on suspicion of wounding. They are aged 18,19 and 20.
Waterstones was been unable to open for Saturday morning due to the police investigation. They tweeted an apology to customers.