The 25-year-old officer was murdered in Omagh in 2011 when a booby-trap car bomb exploded under his vehicle outside his apartment in Highfield Close on April 2 as he made his way to work in Enniskillen.
Dissident republicans were behind the attack, however no one has ever been charged for the murder.
In the last two years, the police say their investigation, and an investigation into several linked incidents, has seen a total of 8,203 items being seized and 15,539 individuals featured.
They also said 122 searches have been conducted in houses, vehicles and land and 19 arrests have been made.
In a statement, the family of Constable Kerr said they remember him “fondly as the loving son and brother that he was and we miss him every day”.
The family added: "We will never forget his caring nature and his sense of humour. As a family, we continue to suffer the devastating impact of having him stolen away in such a vile and cruel way.”
His mum, Nuala, said: “Not a minute goes by where we don’t feel the pain of his loss, and it’s a searing pain."
Meanwhile, Chief Constable Simon Byrne posted to Twitter: ‘Today my thoughts are with the family and friends of Constable Ronan Kerr who was callously murdered 10 years ago. No one deserves to lose their life for bravely serving their community. Our Serious Crime Branch are committed to bringing his killers to justice.’
Detective Chief Inspector John Caldwell, from the Major Investigation Team, said that he still believes there are witnesses in the community 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 10 year anniversary. It is never too late to do the right thing.
“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.
“Their suffering continues every day and they will forever miss their son and brother. I appeal to anyone who has information to search your conscience and bring it to police. I also make a direct appeal to the family and friends of the murderers to come forward. Search your conscience, as now is the time that common humanity should override misplaced loyalty.
“Give us the information we need to take this investigation forward and place these violent terrorists before the courts.”