A woman has been arrested on suspicion of the murder of Ludmila Poletelova, who was found dead at her home in Limavady, County Londonderry on Friday.
Ms Poletelova, who was 61, died as a result of a number of blows to the head, according to a post-mortem examination carried out on Saturday.
Her body was discovered in her flat at Lodge Court on Friday afternoon.
On Sunday evening, police arrested a 45-year-old woman in Limavady and have taken her into custody for questioning.
Two properties in the Limavady area have also been searched by detectives involved in the murder investigation, according to a statement from Det Ch Insp Neil McGuinness.
"Ludmila suffered a violent death which no-one deserves and we owe it to her, and her friends and family, to catch the person responsible and to bring them before the courts," Mr McGuinness said.
"Whilst we are making progress with our investigation I would continue to appeal to anyone with any information, no matter how small or seemingly insignificant, to bring that information to us."
Ms Poletelova was a Latvian national who had lived and worked in Limavady for a number of years.
But she had not been seen by friends or neighbours since Monday, 19 April, according to police.
At about 14: 45 BST on Friday, officers received a report of a "sudden death" of a woman at the flat in Lodge Court, off Main Street.
Police and ambulance staff were deployed to the scene and, following the results of the post-mortem examination on Saturday, a murder inquiry into Ms Poletelova's death was announced.
The victim's family were informed of the investigation on Saturday and at the time, Mr McGuinness said family liaison officers were supporting them "at what is obviously a shocking and horrific time".
He said Ms Poletelova had been subjected to a "vicious attack" and police were "working round the clock" to catch her killer.
Northern Ireland Assembly member (MLA) Caoimhe Archibald said the murder had shocked the community.
"My thoughts and sympathies are with her family, friends and loved ones at this time," the Sinn Féin MLA said.
"The PSNI has now launched a murder inquiry and I would encourage anyone with information which can help to get in contact with the police."
'A place where she should have been safe'
In his statement on Saturday, Mr McGuinness said detectives were "working on retracing her movements over recent days and scouring CCTV footage from shops and businesses in the area".
"I am making an urgent appeal to the public for information'" he said.
"Were you walking or driving in the Main Street area of Limavady any time between last Monday morning, 19th April and the afternoon of Friday 23rd April?
"If you were and you have dashcam footage or saw any suspicious or unusual activity in the area, it is vitally important that you get in touch with police.
"This was a vicious attack on a woman in her own home - a place where she should have been safe and secure."
The detective added: "I want to reassure the local community that we are working round the clock to apprehend the perpetrator."