Joel Richards, 20, was left at Birmingham's City Hospital on Sunday where he died from his injuries.
A 17-year-old boy was arrested on suspicion of murder at a service station on the M40 on Monday evening.
West Midlands Police also stopped a car on the motorway near Oxford and arrested three men and a woman on suspicion of assisting an offender.
Supt Tom Chisholm said:  "This continues to be a fast paced inquiry and we have made five arrests over the bank holiday weekend.
"However, our work is not done and we continue to investigate the circumstances that led to this young man's death.
"We will still continue to liaise with Joel's family and our thoughts remain with them as they continue to come to terms with their loss."
Five people have been arrested after a man left at a hospital died of stab wounds.