A 16-year-old boy was arrested on Tuesday on suspicion of murdering Rhys Jones, the 11-year-old Liverpool schoolboy gunned down on his way home from playing football, Merseyside Police said.
He is the 17th person to be arrested in connection with the murder of the youngster.
Eleven people have been bailed pending further enquiries and five have been released without charge.
Rhys died when he was shot in the neck in a pub car park in the Croxteth area of Liverpool on Aug. 22.
Police are searching for a youth seen on a BMX bicycle in the area at the time. Following the latest arrest, Detective Superintendent Dave Kelly said: "People are aware that we have described one individual firing a gun but, as with any offence, there are various stages and elements to it, including where the gun came from and what happened afterwards.
"When we have grounds to suspect people involved in any stage, they will be arrested in connection with this offence.
"We have a very clear strategy for this investigation and we're determined to leave no stone unturned.
"We're confident about the swift progress we're making and want to thank the public for their ongoing support."
Detectives are continuing to appeal for the driver of a red car to come forward.
It is believed to have been on Fir Tree Drive North at about 7.40 p.m. on the day of the shooting in the Fir Tree pub car park and the driver might have seen a cyclist riding towards Dam Wood.
Rhys's funeral will take place on Thursday.
