Detectives investigating the murder of Constable Ronan Kerr have appealed for information on the 10th anniversary of his death in Omagh in 2011.
The 25-year-old PSNI officer died after a bomb exploded under his car as he left his apartment in Highfield Close at 3.45pm to go to work in Enniskillen.
Detectives from the PSNI's Serious Crime Branch are making a renewed appeal for information.
The officer now leading the investigation, Detective Chief Inspector John Caldwell, said that he still believes there are witnesses who may hold the key to vital evidence.
He said: "Ten years ago today Ronan left his home to travel to work. His job was to protect the community.
"Despicably, people living in his own community planned and plotted to kill him simply because he was a police officer bravely going out every day to protect people and make communities safer places to live and work.
"No one deserves to be murdered because of how they earn their respectable living and I would ask those living in the Omagh area, who know vital information about the bomb attack and those involved, to bring it forward to police on this ten-year anniversary. It is never too late to do the right thing."
Detective Caldwell added: "Ronan's mum and family deserve to have some closure after a decade of intolerable grief.
"It won't take away their pain nor will it bring Ronan back, but seeing someone brought to justice for his sickening murder will allow them to close that chapter of the process at least."
Chief Constable Simon Byrne paid tribute to Ronan: "My thoughts today are very much with Ronan's mother Nuala, his siblings and wider family circle and friends. Ronan's family deserve to see his terrorist killers behind bars where they belong."
