The family of journalist Lyra McKee have urged anyone with a “political agenda” not to use her image.
Dissident republican group the New IRA has been linked to the killing.
Sinn Fein has been criticised for reportedly contacting the group over a potential “co-operation agreement” with an aim to achieve a border poll.
A letter from the party’s chairman Declan Kearney was leaked at the weekend just days before the Stormont election.
Nichola McKee Corner has said that anyone using her sister’s image to promote their own political agenda is causing untold pain and distress to their family.
She was speaking following the publication of a tweet that contained a photograph of Lyra.
The family has requested that the tweet be removed.
“The pain and trauma of Lyra’s murder has not lessened for our family over the last three years,” Ms McKee Corner said.
“Our memories of Lyra are so precious to us and to see her picture used by people who never knew her, who never understood what made her the inspirational person she was just to make some political point or other is heartless beyond words.
“They sully Lyra’s memory. Shame on them,” she added.