Liverpool, England ? Police arrested a third teenager Friday in the shooting of an 11-year-old boy whose death has confronted a shocked Britain with the problem of youth violence and gang culture.

The victim, Rhys Jones, was kicking a soccer ball with friends Wednesday night when he was hit in the back of the neck by a bullet – reportedly fired by one of two youths riding by on a BMX bicycle.

Two youths, ages 14 and 18, were detained by police Thursday on suspicion of murder, and released on bail within hours. Assistant Chief Constable Patricia Gallan said a 16-year-old was arrested Friday.

The tabloid Sun offered a $200,000 reward in today’s edition for anyone who provides police with information that leads to a conviction in the case.

In interviews, Home Secretary Jacqui Smith choked back tears in declaring that the government was seeking answers to the problem of youth crime.

“One of the things I am talking about with the prime minister (Gordon Brown) is where are people getting guns from? How are they getting here?” Smith said.

Britain outlawed the possession of handguns in 1997 in response to the massacre of 16 children, and the country has one of the lowest gun homicide rates in the world – 0.04 slayings per 100,000 people, according to the Geneva-based Small Arms Survey for 2004. The rate is roughly 100 times higher in the U.S.: 3.42 gun murders per 100,000 people.

Police said there was no indication why Rhys was targeted, because he was not known to belong to any gang. He might have been a victim of mistaken identity or was accidentally shot by a teen trying to show off, a police official said, agreeing to discuss the case only if not quoted by name.