The family of murdered journalist Lyra McKee are launching an online campaign appealing for information on her killer ahead of the second anniversary of her death.
Justice4Lyra will go live on Wednesday, when the talented young writer would have been celebrating her 31st birthday.
Her sister, Nichola McKee Corner, said: "Nobody has been charged with shooting Lyra but the PSNI know the identity of the gunman.
"It is so hard for us knowing that he continues to walk around freely while our sister lies in the grave.
"We are launching a website to show people, who didn't know her, what Lyra was like.
"They can read her work, they can hear her talk, they can see how much she had to offer the world.
"We are asking anyone with information or footage that could lead to the arrest and conviction of those who took our sister from us to come forward."
Lyra McKee was shot dead as she stood with her partner, Sara Canning, and local residents beside a PSNI Land Rover in Derry's Creggan estate during a riot in April 2019.
She was hit in the head by a single bullet after a New IRA gunman opened fire on police.
Paul McIntyre (52) of Rinmore Drive in Derry is currently on bail charged with her murder, although it is not claimed that he was the gunman. He denies the charges.
Niall Sheerin (28) from Tyrconnell Street is charged with possessing the gun used in the murder, which he denies.
Christopher Gillen (40) of Balbane Pass faces charges in connection with rioting on the night Lyra was shot.
"Despite 150 brave local people coming forward with information and video footage to the police, the gunman has yet to be charged," Nichola said.
"Lyra was the main carer for our disabled mum, Joan, who died of a broken heart 11 months after she lost her baby girl.
"On her death bed, we promised her that we would continue to fight until we secured justice for Lyra.
"We are keeping that promise."
There have been more than 160 paramilitary-related murders since the 1998 Good Friday Agreement, with a conviction rate of less than 1%.
"We have to be hopeful, despite the statistics," Nichola said.
"We have to believe in the goodness of people to come forward with new information now, just as they did in the aftermath of Lyra's murder.
"The culture of silence that pervades Northern Ireland protects paramilitaries and prevents justice.
"We must change that."
The website includes PSNI video footage from the night of the murder, Lyra's own writings, including articles for the Belfast Telegraph, and tributes to her from journalist friends.
"Doors were not held open for Lyra in the media industry for her to glide through when she started out," Nichola said.
"There were those who made it their mission to try to stop Lyra's blossoming career.
"But with the support of our mum, family and friends - and with her own hard work and determination - Lyra dug a tunnel through the barriers."
Lyra had secured a two-book deal with Faber and Faber, her TEDx talk was watched by almost 150,000 people on YouTube, and her speaking career had taken off as she travelled across the UK and Europe speaking on topics such as the role of working-class people in the media.
"Lyra's driving force in journalism was to give a voice to the voiceless," Nichola said.
"She was a caring, kind and generous person who put the needs of others above her own.
"Her empathy and energy made so many people love her.
"Her murder has left gaping hole in all our lives that can't be filled."
Nichola said that her birthday would be a heart-breaking day for the family.
"If Lyra was alive, I'd be buying her the leather-back notebooks she loved, a new Parker pen, and something to do with Harry Potter.
"JK Rowling was her inspiration. She was a single parent, like our mum, and Lyra grew up reading all her books.
"She loved the idea of magic.
"We can't buy Lyra a present, throw her a party or bake her a cake on Wednesday.
"But we can take our justice campaign online with the website and through Facebook and Twitter.
" It is also our way of honouring our late sister's life and legacy."