Aaron Anthony Thompson, of Port Alberni, was found suffering from stab wounds in the 4800 block of Redford Street shortly after 8 a.m. PT. He died later in hospital.
Police said information given by witnesses led officers to the area of Dry Creek at the east end of Argyle Street, where dogs tracked a man along the creek and up onto Frank Street.
Just after 2 p.m. Monday, police arrested a 25-year-old Port Alberni man. The suspect remains in custody Tuesday, and no charges have been laid.
Cpl. Jen Allan of the Port Alberni RCMP said police are looking to speak with any potential witnesses, and anyone with information about Thompson's death.
"There may be someone in the community who has the one piece of information that investigators require to put the entire picture together, and we are urging them to call us," Allan said.