Paul Erhahon and Kodjo Yenga were both killed by teenage gang membersA senior police officer has called on parents to take more responsibility after 10 teenagers were sentenced over the murder of two schoolboys. Sixteen-year-old Kodjo Yenga and Paul Erhahon, 14, were stabbed in separate incidents in London last year - both had been set upon by teenage gangs. Det Supt Matthew Horne said some were only 13 when the crimes took place. "To their parents I would ask them this: what were your kids doing? Where did you think they were..?" he said. Paul Erhahon was stabbed in the heart with a sword by teenage gang members who wanted to "earn their spurs", the Old Bailey heard. Father's tears Many wore hoods and masks and were armed with baseball bats, knives, swords and a bicycle chain when they carried out their attack near Paul's home in Leytonstone, east London, last April. Paul's father, also called Paul, wept as he read out a victim impact statement in court. He said: "People who have been nurtured to live outside the realms of a decent and law-abiding society murdered my son." Please turn on JavaScript. Media requires JavaScript to play.