A 28-year-old woman has died after she was attacked at the travel agents where she worked.
A man, aged 30, has been arrested on suspicion of murder following the incident at the TUI store in Chapel Street, Southport, at about 13:25 GMT.
Ten police vehicles and two air ambulances attended after receiving reports that a woman had been injured. She later died in hospital.
Merseyside Police believe the incident was "domestic related".
A force spokesman said: "The woman was taken to hospital where she subsequently died from her injuries.
"The woman's next of kin have been informed."
A TUI spokeswoman said: "We regret to confirm that a female member of staff at our Southport TUI retail store tragically died in an incident today.
"We send our deepest sympathies to the friends and family of the staff member involved.
"We're doing everything possible to assist the local police with their investigation and support our customers and staff at this difficult time."