A 16-year-old has been arrested on suspicion of the murder of Liverpool youngster Rhys Jones.A 14-year-old boy and an 18-year-old youth who had earlier been arrested on suspicion of murdering the youngster have been released on police bail.Merseyside Police are examining an abandoned bicycle found in Liverpool, in an area with a different postcode from the shooting, and they are searching for the murder weapon.A police source said: "Rhys was not involved in any form of gang. We are categorising this as a Category A-plus homicide, the most serious investigation to take on. We have made some arrests but this could be a protracted investigation."We're at a very early stage. The 16-year-old boy was arrested this afternoon in the local area and held on suspicion of murder as part of the ongoing investigation."The murder weapon is described variously by witnesses as a black handgun with a long barrel. We don't know what the motive was."Police have appealed directly to the killer to "hand yourself in".Assistant Chief Constable Patricia Gallan also asked the public for help to find who shot the 11-year-old football fan as he walked home from football practice on Wednesday.Ms Gallan said: "I need more help in solving this crime. We need to get this killer off the streets."Rhys's heartbroken parents have also pleaded for help in finding their "baby's" killer. His mum, Melanie, cradled him in her arms in his dying moments after he was gunned down outside the Fir Tree pub in Croxteth.Mrs Jones, 41, said: "Our son was only 11, only a baby, this should not happen, this should not be going on , please help us. I know people must be frightened but they can't leave this killer out there."It could be their son, their brother next time, because it will happen again."Rhys's father, Stephen, 44, said: "People are saying to me, 'wrong time, wrong place'. It shouldn't be a case of wrong time, wrong place. It shouldn't happen in this country. Somebody out there knows who's done it."Residents said shots were fired by a teenager who rode past the pub on a black BMX bike. The suspect is described as a slim white boy aged 13 to 15, around 5ft 8ins tall and wearing dark clothes, including a hoodie top with a peak, and white trainers.© Independent Television News Limited 2007. All rights reserved.