A police watchdog is investigating a complaint from the family of murdered journalist Lyra McKee over PSNI actions on the night she was killed.
It comes as police revealed they know the identity of 29-year-old Ms McKee's killer, but do not have the evidence to put it before the courts.
She was shot dead in April 2019 while observing a riot in the Creggan estate in Derry.
The complaint to the Police Ombudsman from her family relates to aspects of the policing operation in the city on the night of her death.
It concerns the decision of the PSNI to search a house in Creggan on April 18.
Nothing was found during the search and while it was going on, rioting broke out during which Ms McKee was fatally shot.
The New IRA has admitted responsibility.
The DUP's Mervyn Storey said the Ombudsman's review should not detract from the actions of terrorists on the night of the murder.
"The office of the Police Ombudsman should be afforded space to come to its own conclusion," he said.
In a statement, the McKee family said: "Whilst we hold Lyra's killer and their associates completely responsible for her murder, we have asked the Police Ombudsman to investigate the aspects of the policing operation on April 18, 2019.
"The Police Ombudsman investigation is completely separate to the ongoing murder investigation.
"We consider this a very personal family matter and have no further comment."
PSNI Detective Chief Superintendent Raymond Murray acknowledged the complaint but defended police actions.
"The Ombudsman will conduct its investigation and it will come to its own conclusion," he said.
"What I will say is that the officers acted in good faith with the information at the time. That is all we can do."
Separately, SDLP MLA and Policing Board member Dolores Kelly accused the PSNI of failing the people of Northern Ireland.
She criticised the PSNI for not catching dissident republican killers involved in the high profile murders of Ms McKee and 43-year-old Jim Donegan, who was shot outside a school in west Belfast in December 2018 as he waited to pick up his son.
"I think the biggest test in terms of adequacy of the police response lies in the conviction of the people responsible and to date, unfortunately, in both cases, no one has yet been brought before the courts, either directly charged with the murder or assisting those responsible," she said.
"I think not only will people be disappointed but they will be angry that no one has been charged."
Det Chief Supt Murray defended the police response to the murders.
"Those investigations are very far from over and so I do feel in all honesty that these remarks potentially are premature," he said.
"These investigations still have quite a considerable way to travel. Dissident republican murders are extremely difficult.
"I will go so far as to say we operate in one of the most challenging investigative environments in Europe."
He added that police knew the identity of Ms McKee's killer but given the difficulties in gathering evidence they were not in a position to put it before the courts.
The Police Ombudsman has been approached for comment on the matter.