bob. "60 minutes" has been on the bulger case for years. the late ed bradley interviewed two of bulger's closest mob lieutenants. in 2001, ed spoke with eddie mackenzie, the first member of bulger's gang ever to speak publicly. >> he had such a stare of blankness, no compassion in his eyes, ed, that just would horrify anybody. you could be 6' 6", 360 pounds, the toughest guy... i've seen people almost go to the bathroom in their pants in his presence, he was so scary. >> pelley: then, in 2006, ed spoke to kevin weeks, a mob lieutenant who knew bulger better than most. >> oh, he stabbed people, he beat people with bats, he shot people, strangled people, ran them over with cars. >> you said also that he liked killing. >> yeah. >> explain that to me. >> after he would kill somebody, he'd... it was like a stress relief, you know? he'd be nice and calm for a couple weeks afterwards, like he just got rid of all his stress. >> by killing? >> yes. >> that's a bizarre way to get rid of stress. >> pelley: kevin weeks, the man you just heard from, led the f.b.i. to where some of bulger's alleged victims were buried. he is likely to be a witness at trial. it has