Aontú councillor Denise Mullen says she has been left shaken after receiving hate mail about her father who was murdered by loyalists almost 50 years ago.
Her father, SDLP activist Denis Mullen (35), was shot dead by the UVF at his home near Moy, Co Tyrone, in September 1975.
The killing was carried out by the Glenanne Gang, which included members of the RUC, UDR and UVF.
Ms Mullen last night said she contacted the PSNI after a letter was addressed to her at the offices of Mid Ulster District Council.
She said the hand-written note included "hurtful and personal" comments about her late father.
She said the correspondence included clippings from local newspapers about a recent commemoration for eight Protestant construction workers who died when the IRA detonated a bomb at Teebane Crossroads, near Cookstown, in January 1992, as they returned from a British army base.
The latest letter comes just months after former loyalist Garfield Beattie was jailed for 17 months after he sent a threatening letter to Ms Mullen signed 'East Tyrone UVF'.
Beattie served 16 years for his part in three murders including that of Denis Mullen.
Ms Mullen last night said the latest incident is upsetting.
"I am shaken and it just annoyed me," she said.
"I am worried now about what will follow from this."
Ms Mullen said she has told her 79-year-old mother Olive about the letter.
"It's terrible we have to endure this," she said.
"You are fighting the system for evidence and meanwhile you have to put up with this."
A spokesman for the PSNI said: "Police received a report of suspicious circumstances" in the Moy area and "enquiries are ongoing.”
"This is currently being treated as a hate crime."