Detectives investigating a double murder at a massage parlour have yet to trace two clients who visited the premises on the day of the killings.
Detective Chief Inspector Sheila Thornes, who is leading the inquiry, said officers had now traced five of seven customers known to have visited Rachael's Health Studio in Shrewsbury on July 1.
The bodies of Annie Eels, a receptionist, and Samantha Tapper, were discovered in a downstairs room of the parlour at 13 Frankwell shortly before 2.45am on Sunday July 2.
Both had severe head injuries and police believe they were killed between 3pm and 5pm the previous day.
Ms Thornes said: "Considerable progress has been made and we have been able to establish several specific lines of inquiry."
Although officers are keeping an open mind as to whether a client was responsible for the deaths, police believe seven customers visited the parlour on July 1, five of whom have been traced.
"We are still trying to trace the two outstanding clients," said DCI Thornes. "In addition to the visiting clients, it is also known a number of people telephoned the premises that day. We know there were 58 separate telephone callers and we are currently identifying these callers, who will also be interviewed. In addition, there are a large number of clients - more than 70 - who did not visit on the day who we are in the process of contacting and interviewing."
Police are still searching for the murder weapon and have not said what they believe it to be.