Christine James' body was found at her flat in Century Wharf in Cardiff Bay on Wednesday, March 2.
A 36-year-old man has been arrested on suspicion of murder and is currently in custody at Cardiff Bay Police Station.
South Wales Police is continuing to investigate her murder and is still appealing for information.
A 66-year-old man, arrested on suspicion of murder was released from police custody on Monday 7th March.
Detectives have been granted, by Cardiff Magistrates’ Court, a further period of 36 hours to question him at Cardiff Bay Police Station following his arrest on Wednesday night.
Senior Investigating Officer Detective Chief Inspector Ceri Hughes said: “Mrs James’ family are being supported by a family liaison officer at this extremely distressing time and a murder enquiry is underway to establish the circumstances leading to her death.
“Although one man has been arrested and remains in custody, we are still very much appealing for information and for witnesses to come forward.”
Christine, 65, moved from Cowbridge to Century Wharf, Cardiff Bay, in November 2015.
She lived alone in her fourth-floor flat in Dubrovnik House, Hansen Court, and parked her 13-plate 5-door blue BMW 118 car in underground allocated parking.
She was last seen returning to the complex at around 12.30pm on Friday, February 26 and friends spoke to her on the telephone at around 2pm that day.
On the Saturday she was due to travel to Gatwick Airport to catch a flight to Florida.
Following concerns by relatives that she never arrived in London, officers conducted a welfare visit to her flat on Wednesday, March 2 where her body was discovered at around 2.15pm.
Detectives would like to hear from:
· Anyone who saw or spoke to Christine after around 12.30pm on Friday.
· Witnesses who might have information about someone trying to gain entry to the complex.
· Residents who might have noticed or spoken to someone enquiring about Christine, her flat or car,
· Friends or acquaintances of Christine living in Century Wharf or elsewhere who have not yet been spoken to by police.
DCI Ceri Hughes said: “Although we are still carrying out house to house enquiries in Hansen Court, there might be people in the Century Wharf complex or elsewhere who are friends with Christine who we are not aware of and have not spoken to us.
“We would ask anyone who knows Christine or who noticed anyone acting suspiciously in the area to please contact us as they may have vital information that could assist our investigation.”
Anyone with information is asked to contact South Wales Police on 101 or Crimestoppers anonymously on 0800 555 111 quoting occurrence number *072884
* South Wales Police has referred the matter voluntarily to the Independent Police Complaints Commission.