The deputy First Minister has hit out at the police investigation into the dissident republican murder of Catholic officer Ronan Kerr.
Martin McGuinness was among the senior figures who led cross-community condemnation of the killing in April.
But in an unusual step the Sinn Fein representative has now criticised the probe and questioned the arrest of a 22-year-old man in Coalisland, Co Tyrone, who has since been released by police.
Last night, four other men arrested in connection with the murder were also released.
Mr McGuinness said: "I have been in contact with the PSNI at the top level to register my dissatisfaction and annoyance at the operation in Coalisland.
"Nobody who knows this young man and his family are in any doubt that he has no link whatsoever to the murder of Ronan Kerr.
"The nature of the operation has caused anger in the local community. That is a reality the PSNI will now have to face."
In a response the PSNI said it carried out its investigations to the highest standards "without fear or favour in accordance with the law".
Constable Kerr was killed when a booby-trap bomb exploded under his car outside his home in Omagh, Co Tyrone, on April 2.
Mr McGuinness had famously branded dissidents as traitors to Ireland after earlier attacks by the groups opposed to the peace process.
Constable Kerr's murder sparked an unprecedented display of political unity against the violence.
Mr McGuinness was prominent as the leaders of unionism and mainstream republicanism stood shoulder-to-shoulder with the police at the young officer's funeral.
On Tuesday detectives investigating the murder, as well as what police described as "associated incidents", arrested five men ranging in age from 22 to 46.
The operation, which included searches at a number of locations and involved 200 officers, was followed yesterday by the arrest of a 23-year-old woman.
But last night, after police confirmed the release of the 22-year-old man who had been detained in Coalisland and four others, Mr McGuinness issued his broadside against the investigation.