Sinn Féin has condemned the arrest of an independent republican candidate outside the Assembly election count centre in Omagh yesterday.
Gerry McGeough had been living in the South, but recently returned to the North to contest the election in opposition to Sinn Féin.
His arrest yesterday is related to the attempted murder of a UDR member in 1981.
The husband of a Sinn Féin councillor in Monaghan was also arrested in the border town of Aughacloy in connection with the case.
Sinn Féin president Gerry Adams has called for the men to be released, while local Sinn Féin MP Michelle Gildernew accused the PSNI of orchestrating the arrests as a politically-motivated stunt.