Stephen O Rourke was found guilty of murder at the Old Bailey on Tuesday
Rocky Djelal, 38, was stabbed to death in broad daylight on Halloween in 2018
The attack came on the 18th anniversary of the funeral of O Rourke s murdered brother Michael Paddy O Rourke
Djelal had been arrested but no one has ever been charged in the unsolved case
Stephen O Rourke faces life in prison and will be sentenced at a later date