Almost two years after the death of greyhound trainer John Burrows in the small NSW central west town of Portland, police have made a breakthrough in the case that shocked the close-knit community.

Police are urging the community to help them put together the final pieces of the puzzle surrounding the death of the popular 58-year-old father of three.

Investigators have determined that the improvised explosive device (IED) which killed Mr Burrows early on the morning of July 24, 2015 was detonated remotely with a radio-controlled receiver.

Chifley Local Area Command crime manager, Detective Chief Inspector Luke Rankin, said someone in the small community of 2000 near Lithgow must have information about the origin of the radio-controlled receiver.