A man flew to Bangladesh on a flight from Heathrow Airport the day after killing a 20-year-old found collapsed outside a newsagents, a court heard.
Waryam Hussain died from a single stab wound near McColl's on Bishopscote Road, Luton, on 6 May.
Luton Crown Court heard he was knifed by Majharul Islam, who "left him there to die" before fleeing the country.
Mr Islam, 20, of Walcot Avenue, Luton, was arrested on his return to the UK on 22 May. He denies murder.
Prosecutor Michael Speak told the court the two men, who were known to each other, met close to Mr Hussain's home on Bristol Road.
He told the jury it was there that Mr Islam fatally stabbed the victim near double mini-roundabouts at the junction of Bishopscote Road and Bristol Road at about 16:35 BST and then "ran away".
Mr Speak said Mr Hussain "ran or staggered in a state of shock or fright" across the roundabouts and collapsed outside McColl's.
He continued: "He fell onto the pavement. People started to gather. The sad fact is that that was the end of his life. He never got up. He never said anything about what happened.
"Despite best efforts of numerous paramedics and the efforts of specialist doctor who came in an air ambulance, it was impossible to save his life. He died on that pavement outside that shop."
Mr Islam was identified after police released CCTV footage the following week and checks with customs found he had got a 22:15 flight from Heathrow to Bangladesh on 7 May, the court heard.
The jury was told he returned back to Gatwick Airport on 22 May, where he was arrested.
The court heard Mr Hussain had planned to marry his long-term girlfriend Saibah Javid, who dropped him off at his home at about 16:00 and said "nothing was going on that signalled there was trouble coming".
The trial continues.