PC Greg Turnbull recalled attending to an injured Mohammed Abdi in Edinburgh's Duddingston area last May.
The officer yesterday told the High Court in Glasgow how he lifted the 25 year-old's T-shirt and found a wound on his body.
He added: "I tried to cover the wound and then started CPR."
The policeman also recalled Mr Abdi "gurgling" as he treated him.
Prosecutor Iain McSporran asked: "Any sign that your efforts were succeeding or not?".
The witness replied: "No."
The court heard Mr Abdi was rushed to hospital, but was later pronounced dead in the early hours.
The evidence was heard at the trial of Mohamud Mohamud, 30, Ahmed Ahmed, 28, Cadil Huseen, 23, Hussein Ali, 26, 30-year-old Liban Ahmed - also known as Jama - Said Fadal, 32, and Said Tarabi, 27.
They deny murdering Mr Abdi.
The case, which is being heard before Judge Lord Turnbull, continues.