Brothers Gary Anderson (25) and Sean Anderson (23), both of Grafton Street, and Michael Dunlop (21), of Fern Park in Derry, are all charged with the murder of father-of-five Karol Kelly in Derry on March 4, 2018.
Dunlop is further charged with attempting to cause grievous bodily harm with intent on Mr Kelly and doing an act with intent to pervert the course of justice on the same date by attempting to conceal knives.
Jonathan Irons, who told the court he was an expert on DNA, said he examined certain items from Grafton Street.
He gave evidence of examining two knives on which, he said, he found DNA belonging to Karol Kelly.
He also said he examined trainers belonging to the defendant Gary Anderson on which he found blood stains matching the profile of the deceased.
The witness said he also examined items belonging to the defendant Sean Anderson and found blood stains consistent with both the defendant and Mr Kelly.
The jury was told that blood stains were also found on a Ford Transit Minibus which, the DNA expert said, would have come from being in contact ‘with a wet source of blood.’.
The witness said that seven of the blood stains on the vehicle matched the profile of Karol Kelly.
The trial continues.