A third person has been arrested after a 28-year-old council worker was shot dead in Liverpool.
Ashley Dale was found with gun shot wounds to her body in the back garden of a house in Old Swan on Sunday 21 August.
She was taken to hospital but died a short time later.
Officers believe the 28-year-old, who worked in the environmental health team at Knowsley Council, was not the intended target of the attack.
Police have said a 27-year-old man from Dovecot has been arrested on suspicion of murder and possession of a firearm. He has been taken to a police station for questioning and remains in custody.
Ms Dale's death was one of three fatal shootings in the city within a week.
Olivia Pratt-Korbel, 9, was shot dead in her own home by a masked gunman the day after Ms Dale was killed.
The third suspect has been held in relation to Ms Dale's death after a man and a woman arrested as part of the investigation were released on bail.
The 25-year-old man had been arrested on suspicion of her murder, while the 21-year-old woman had been arrested on suspicion of assisting an offender.
Both people have been conditionally bailed to a later date, pending further inquiries, Merseyside Police said.
Detective Chief Inspector Cath Cummings said: "We have now made three arrests and extensive enquiries continue to establish the motive behind this attack, and to identify all those involved.
"Although progress is being made, I'd still like to urge anyone with information who has yet to come forward to do so as soon as possible. Please do not assume that what you know has been passed on by someone else, or that it is not significant enough to bring to our attention. I have a team of dedicated detectives who will make that assessment. Help us find justice for Ashley's family, and for a community devastated by her loss."
Merseyside Police has made hundreds of arrests as part of a crackdown on organised crime after three fatal shootings in one week.
Sam Rimmer, 22, was killed in a drive-by shooting in Dingle on Tuesday 16 August.
Ms Dale was then killed five days later, before Olivia was shot on Monday 22 August.
It has emerged Olivia was scooped up by police and taken to hospital after being shot in the chest by a balaclava-clad gunman who had entered her house while chasing his intended target.