Police were called to Walnut Street in the town at shortly before 4pm on Saturday (April 3) to a report of an assault.
A man in his 50s was taken to hospital with a number of stab injuries described as serious. His condition is stable.
Officers now want to speak to Fayaz Waka, 22, who is from Blackburn.
He is described Asian, 5ft 9ins tall, bald with a short trimmed beard and of a slim build.
Det Sgt Steve Craig, of East CID, said: “We have made significant progress with this investigation and we now need to speak to Waka. I would ask anybody who sees Waka or has any information on his whereabouts not to approach him, but to call police as soon as possible. If Waka sees this appeal, I would encourage him to attend his nearest police station or contact police straight away.”
Last week, as part of the investigation, Mahtab Hanif, 22 and Ramzan Hanif, 24, both of Goldhey Street, Blackburn, were charged with Section 18 wounding. They appeared before Blackburn Magistrates on Friday and were remanded into custody.
Anyone with information on Waka’s whereabouts should contact police on 101 quoting log 1092 of April 3rd.
Alternatively contact independent charity Crimestoppers on 0800 555 111.