A man has been arrested in connection with the twin murder of Indian-origin Avtar Singh Kolar and his English wife in Birmingham, the West Midlands police said on Saturday.
Officers working as part of Operation Tiler executed a warrant at a house in Birmingham on Friday night and arrested a 24-year-old man as part of their investigation.
He has been taken to a police station in the West Midlands where he is being questioned on suspicion of murder.
The police launched the major investigation on Wednesday after the bodies of Carole and Avtar Kolar were found inside their home by their son Jason Kolar, who is a serving officer with the West Midlands Police.
Forensic post mortem examinations have been conducted, which confirmed that both Avtar Singh and Carole died as a result of blunt force trauma to the head.
Both had been struck a number of times.
Two of the couple's children -- Michelle Kirwan and Avtar Kolar -- spoke at a media conference on Thursday of their heartbreak and devastation.
Charity organisation Crimestoppers has put up a reward of up to 10,000 pounds for information leading to the arrest and conviction of the person or persons responsible for the deaths.
Detective Superintendent Richard Baker, who is leading the murder investigation, said, "This was a horrendous attack. We continue to follow a number of lines of enquiry and we thank those who have called us so far. We encourage anyone with information to speak to us no matter how insignificant they feel the detail is".