>> he was fighting, and he was killed. >> pelley: yusuf jama was also killed. you responsible for their deaths? >> yeah, i believe i am responsible for their deaths, and i think about that every day. >> pelley: this is the fascinating story of how a dozen american teenagers decided to fight for isis, and how the somali community in minneapolis is fighting to save its youth. the story is this sunday on "60 minutes." isis, of course, is still in control of iraq's second largest city, mosul, but iraqi and kurdish forces are closing in. u.s. warplanes and special forces are in the fight, and holly williams is there. >> reporter: thousands of civilians are escaping from isis as the extremists retreat from their villages. this offensive has killed hundreds of isis fighters, according to the u.s. coalition, with over 300 square miles clawed back by iraqi and kurdish forces to the east and south. but they still haven't entered mosul itself. at the american base south of mosul, major chris parker told us protecting the city's one million civilians will make the fight mo

>> he was fighting and he was killed. >> reporter: yusuf jama was also killed. are you responsible for their deaths? >> yeah. i believe i am responsible for their deaths. and i think about that every >> this is the fascinating story of how a dozen american teenagers decided to fight for isis and how the somali community in minneapolis is fighting to save its youth. the story is this sunday on "60 minutes." >>> isis, of course, is still in control of iraq's second largest city, mosul, but iraqi and kurdish forces are closing in. u.s. warplanes and special forces are in the fight, and holly williams is there. as the extremists retreat from their villages. this offensive has killed hundreds of isis fighters, according to the u.s. coalition, with over 300 square miles clawed back by iraqi and kurdish forces to the east and south. but they still haven't entered mosul itself. at the american base south of mosul major chris parker told us protecting the city's 1 million civilis more difficult. >> air strikes do become more complicated when you move into a major metropo

the first two reached syria, yusuf jama, and abdi nur. nur sent back facebook pictures. >> warsame: i remember him telling me, you know, "i'm having the time of my life," and he was fulfilling his dream or on his way to heaven. >> pelley: what happened to him? >> warsame: i believe he's dead. >> pelley: how did that happen? >> warsame: he was fighting, and he was killed. >> pelley: yusuf jama was also killed. are you responsible for their deaths? >> warsame: yeah, i believe i am responsible for their deaths, and i think about that every day. >> pelley: and if you had been able to get to syria, what do you think would have happened to you by now? >> warsame: i probably would be dead right now. >> pelley: after your friend, abdi nur, left minneapolis, his mother was trying to find him. she was desperate. >> warsame: she was desperate. she needed answers. and i did the unthinkable and i lied to her, and i told her that i didn't know where her son was. >> pelley: she was trying to save his life. >> warsame: yeah. that was very evil of me to d

>> he was fighting and he was killed. >> reporter: yusuf jama was also killed. are you responsible for their deaths? >> yeah. i believe i am responsible for their deaths. and i think about that every day. >> this is the fascinating story of how a dozen american teenagers decided to fight for isis and how the somali community in minneapolis is fighting to save its youth. the story is this sunday on "60 minutes." >>> isis, of course, is still in control of iraq's second largest city, mosul, but iraqi and kurdish forces are closing in. u.s. warplanes and special forces are in the fight, and holly williams is there. as the extremists retreat from their villages. this offensive has killed hundreds of isis fighters, according to the u.s. coalition, with over 300 square miles clawed back by iraqi and kurdish forces to the east and south. but they still haven't entered mosul itself. at the american base south of mosul major chris rk protecting the city's 1 million civilians will make the fight more difficult. >> air strikes do become more complicated when you move into

. >> pelley: yusuf jama was also killed. are you responsible for their deaths? >> warsame: yeah, i believe i am responsible fo and i think about that every day. >> pelley: and if you had been able to get to syria, what do you think would have happened to you by now? >> warsame: i probably would be dead right now. >> pelley: after your friend, abdi nur, left minneapolis, his mother was trying to find him. she was desperate. >> warsame: she was desperate. she needed answers. and, i knew where he was going. and i did the unthinkable and i >> pelley: she was trying to save his life. >> warsame: yeah. that was very evil of me to do. >> pelley: as more of warsame's group applied for passports, one of them was evasive about where he was going, and a passport official passed along his suspicions. the f.b.i. got involved and convinced one of the conspirators to cooperate. >> andrew luger: he ended up wearing a recording device for the ways that we have such good insight into the thinking of these co-conspirators. >> pelley: u.s. attorney andrew luger ran the prosecution.