A murder victim whose body was found at a flat in west Belfast may have died more than two years ago.
Marie Conlon, 68, was discovered on Friday by officers after concerns were raised about her welfare.
A 23-year-old man was arrested on suspicion of murder.
PSNI officers had forced entry to her Larkspur Rise home and discovered her dead in bed.
Detective chief inspector Alan Dickson said: "It was apparent that she had lain undiscovered for some time."
A post-mortem examination was carried out and the results suggest that the death may have been suspicious.
Further testing is due to take place.
Ms Conlon was last seen in January 2015 and police believe her death occurred then.
In a statement, her family said: "We are shocked and heartbroken to learn about the loss of our beloved sister, Marie Conlon.
"The tragic circumstances of her death make it all the more difficult to comprehend and accept.
"Marie was very much loved by her family and will be mourned greatly. She was a very independent person.
"Numerous attempts had been made to contact her in person, and by other means, over the course of the past two years but at no point were suspicions raised that she had been deceased. It is only with hindsight that the unimaginable now seems possible.
"We have been working closely with the PSNI to bring this devastating situation to an end. We hope and pray that justice will be done and ask for privacy as we grieve the loss of our sister."
SDLP councillor Brian Heading said: "This was a heinous crime against a vulnerable member of our community.
"Local people are absolutely shocked that something like this could happen here."