A man told a jury he would be "dead in a week" if he had "grassed" his friend to police for the Boxing Day killing of an Indian student in Salford.
Kiaran Stapleton, 21, smirked or laughed after shooting Anuj Bidve, 23, in the head at close range after asking him the time, Manchester Crown Court has heard.
Ryan Holden, 20, who was with Stapleton at the time of the shooting, said he feared for his family if he had gone to police after the incident in the early hours of Boxing Day last year.
Mr Bidve, in the UK to study at Lancaster University, was with eight Indian friends walking through the Ordsall area of Salford on their way to the Boxing Day sales when he was fatally injured.
Stapleton and Holden were arrested days later but Holden went from suspect to witness after telling police who was responsible.
Stapleton has admitted he pulled the trigger and has pleaded guilty to manslaughter on the grounds of diminished responsibility, but denies murder.
Simon Csoka QC, defending, asked Holden, who gave evidence from behind a curtain over the witness box, why he did not give police an anonymous tip-off about who was responsible.
"If I had done I would have been dead in a week," the witness replied, adding: "They all live near there.
"If you could do that to a random stranger, what would you do to someone who was classed as a grass?"
After the shooting both men fled to Stapleton's home on the Ordsall estate nearby where they showered and put on fresh clothes