Detectives have arrested a man in connection with the fatal shooting of 53-year-old Jacqueline Rutter in Wirral last month.
The man, 24 and from Birkenhead, was arrested earlier this week and has been released on conditional bail pending further enquiries.
Two further men previously arrested, aged 44 and 52, remain on conditional bail.
Police are continuing to appeal for information in connection with the murder, which occurred at a property in Meadowbrook Road, Moreton, in the early hours of Sunday 30 October.
Detective Chief Inspector Steve McGrath, the Senior Investigating Officer, said, “Progress is being made in our investigation but we don’t want anyone to see arrests and think we don’t still need any information which is out there.
“If you know anything and have yet to come forward, please do so. What you may know or have captured may seem insignificant, but could still form a vital part of this investigation.
“Let us make that assessment.”
Anyone with any information can contact police via social media @MerPolCC or call 101 or Crimestoppers anonymously on 0800 555 111 quoting reference 22000796038.