Two female police officers, named as 32-year-old Fiona Bone and 26-year-old Nicola Hughes, have been shot dead during the arrest of a murder suspect in Greater Manchester
Dale Cregan, 29, has been arrested in connection with the officers' deaths. He was being sought in connection with separate gun and grenade attacks that killed a father and son.
The officers were attending a "routine incident" at Abbey Gardens in Hattersley, Greater Manchester, police said.
Neither officer was armed.
Dale Cregan, who is wanted for two murders, gave himself up to police.
A £50,000 reward had been offered for information leading to the arrest of Cregan who police wanted to speak to about the murders of David Short, 46, and his son Mark, 23.
David Short was killed at his home in Folkestone Road East, Clayton, Manchester, on August 10, while Mark was gunned down at the Cotton Tree pub in nearby Droylsden, on May 25.
A gunman walked into the pub and fired shots which injured three other men.
A post-mortem examination showed Mark Short died from a gunshot wound to the neck.
Four men have been charged in connection with his murder and are due to enter pleas at Manchester Crown Court in November.
Earlier this month a 33-year-old man also appeared at Manchester Crown Court charged with the gun and grenade murder of David Short.