ans, including american journalist james foley and steven sotloff and american aid worker keet peter cassic in syria in 2014. his brutality and anonymity earned him the name jihadi john. the gruesome videos presented the world with a terrifying image of the islamic state and were a powerful propaganda tool for the terror group. this morning british prime minister david cameron praised the u.s. mission. >> he was intent on murdering many more people. so this was an act of self-defense. it was the right thing to do. >> reporter: emwazi, a british citizen believed to be in his mid-20s, born in kuwait, raced in london. a graduate from the university of westminster, he had a degree in computer programming. he first came to the attention of british intelligence in 2009, who believed he was planning to join al shabaab in somalia. he disappeared from his family's london home in 2013 and traveled to syria. his rise among the ranks of isis as is what motivated >>> we leave you with more on the paris terror attacks and the international show of support that followed. >> it's an attack not just on the

. >> reporter: one after another, he presided over the murders of foley, steven sotloff, peter cassic >> we'll cut the necks of your people. >> reporter: earlier this year, his true identity was identified as mohammed emwazi. seen here wearing an american baseball cap. the son of kuwaiti parents who emigrated to the united kingdom. even as a schoolboy in london, emwazi was spotted by teachers as having a violent streak. one teacher told the bbc that at the age of 11, he was put in anger management therapy. >> we'd find that he'd get very angry and worked up. it would take him a long time to calm himself down. >> reporter: flaunting his role as executioner once he joined isis, with his piercing eyes and gravelly voice, emwazi became one of the world's most wanted men. in a statement to abc news, the parents of murdered hostage james foley said the air strike against jihadi john was of small solace. "this huge effort to go after this der ranged man filled with hate when they can't make half the effort to save the hostages when the hostages were still alive. it's unfortunate the governme

. >> reporter: one after the other, he presided over the murders of foley, steven sotloff d peter cassic, two britons and two japanese hostages. >> we'll cut the necks of your people. >> reporter: earlier this year, his true identity was identified as mohammed emwazi. the son of kuwaiti parents who emigrated to the united kingdom. even as a schoolboy in london, emwazi was spotted by teachers as having a violent streak. one teacher told the bbc that at the age of 11, he was put in anger management therapy. >> we'd find that he'd get very angry and worked up. it would take him a llng time to calm himself down. >> repororr: f funting his role as executioner once he joined isis with his piercing eyes and gravelly voice, emwazi became men. in a statement to abc news, the parents of mururred raj james foley said the streak against jihadi john -- air strike against jihadi john was of small soes as "it's unfortunate that the government doesn't get. it they think it gives us solace but it doesn't. brian red cross, abc news, new york. >> interesting to hear the comment. it is so heart wrenching fo

ans, including american journalist james foley and steven sotloff and american aid worker keet peter cassic in syria in 2014. his brutality and anonymity earned him the name jihadi john. the gruesome videos presented the world with a terrifying image of the islamic state and were a powerful propaganda tool for the terror group. this morning british prime minister david cameron praised the u.s. mission. >> he was intent on murdering many more people. so this was an act of self-defense. >> reporter: emwazi, a british citizen believed to be in his mid-20s, born in kuwait, raced in london. a graduate from the university of westminster, he had a degree in computer programming. he first came to the attention of british intelligence in 2009, who believed he was planning to join al shabaab in somalia. he disappeared from his family's london home in 2013 and traveled to syria. his rise among the ranks of isis as is what motivated >>> we leave you with more on the paris terror attacks and the international show of support that followed. >> it's an attack not just on the people of france. but this is