Mr. Brown, chairman of the Wolfe Tones GAA club in Bellaghy, was abducted and murdered by loyalists on May 12, 1997.
It is believed the Loyalist Volunteer Force (LVF) were responsible for the murder of the 61-year-old father-of-six.
Patsy Kelly was just 35-years-old when he was abducted and murdered after leaving the Corner Bar in Trillick, County Tyrone, where he worked in the early hours of July 24, 1974.
The independent nationalist member of Omagh District Council was a married man with four children.
Last year the Police Ombudsman concluded that a UVF unit from Fermanagh ‘were either directly, or indirectly, linked to Mr Kelly’s murder and other terrorist attacks’ and that ‘intelligence indicated that the UVF unit was assisted in their activities by a number of identified RUC and UDR members’.
The Ombudsman concluded, however, that there was no evidence RUC Special Branch shared this intelligence with the murder investigation team.
"The senior investigating officer has consistently stated that he did not receive intelligence at any point linking UDR members and other individuals to Mr Kelly’s abduction and murder and that, had he been supplied with relevant intelligence, he would have made arrests.
"Based on the available evidence and his consistent accounts, the Ombudsman accepts that none of the intelligence gathered by RUC Special Branch was disseminated to him,” the Ombudsman Marie Anderson said.
Supporters gathered at Free Derry Corner for the rally at 2pm on Sunday before marching to Celtic Park where double-header National League hurling and football matches between Derry and Tyrone were taking place.
1. Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney
Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney Photo: George Sweeney
2. Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney
Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney Photo: George Sweeney
3. Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney
Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney Photo: George Sweeney
4. Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney
Relatives and supporters march from Free Derry Wall to Celtic Park, on Sunday afternoon, to protest against the British Government’s Legacy Bill’s lack of investigation into the deaths of Sean Brown and Patrick Kelly. Photo: George Sweeney Photo: George Sweeney