Police have released a picture of 17-year-old, Kielan Blakey, whom they wish to speak to.
This comes after another 17-year-old was approached and stabbed in the buttock outside Waterstones on Church Street.
Blakey or anyone with information of his whereabouts, is asked to contact police
He is described as white, around 5ft 7ins, and of slim build.
The incident happened on Saturday (8th September) at 5:45pm.
The wounded teenager was taken to Royal Preston Hospital for treatment.
He has since been discharged.
DC Jane Jacques from Preston CID said: “We need to speak to Blakey and it’s important we find him urgently.
“If you have seen him or know where he is, please get in touch.
“I would urge the public not to approach him but to instead contact the police.”
Anyone with information can email email@example.com or firstname.lastname@example.org.
Alternatively you can call Preston CID on 01772 209622.
If you fail to get an answer, you can ring 101 quoting crime reference SA1819046.
Crimestoppers can be contacted anonymously on 0800 555111 or online at crimestoppers-uk.org.