Detectives investigating the shooting of a 17-year-old boy have arrested two more teenagers.
Lewis O'Brien was shot inside a house in Huyton, Merseyside, yesterday afternoon.
The youngster, who neighbours said was nicknamed "OB", was pronounced dead on arrival at hospital.
An 18-year-old man was arrested last night and two youths, aged 15 and 17, were held by police today.
All three remain in custody, where they are being questioned on suspicion of murder.
A 39-year-old woman, who was arrested overnight on suspicion of assisting an offender, also remains in custody, Merseyside Police said.
Officers were called to the house, on Hathersage Road, shortly before 4pm yesterday.
Detective Chief Inspector Richard Carr said detectives are still trying to piece together what happened in the lead-up to the shooting.
"I would like to appeal to anyone with any information about the incident or events leading up to it to come forward," he said.
"This incident has resulted in a young man's life being needlessly cut short.
"There is no place for guns on the streets of Merseyside and with the help of, and information from, the community we will relentlessly pursue this investigation."
Mr Carr said police patrols in the area have been stepped up to reassure residents.
The house where the shooting took place remained sealed off and only residents were allowed in and out of the immediate scene.Reuse content