>> sallee: no, i do not. i tell you you have a right to talk to a lawyer if i'm going to ask you incriminating questions. if we're talking about your becoming an informant, i don't have to tell you that you have a right to a lawyer. >> weber: all right... >> stahl: that's because, since police often recruit confidential informants before charging them and without arresting them, they're not obligated by law to read them their rights. and weber didn't with andrew sadek. he told us sadek made three successful undercover drug buys as a c.i., half the number he'd been told was required of him. weber says sadek was warned he would soon be charged if he didn't continue. then one night, a few weeks shy of graduation, security cameras snapped these pictures of sadek walking out of his dorm at 2:00 a.m. on a thursday morning. a day and a half later, he had not come back. >> tammy sadek: we got a call from the campus at about noon on friday. >> stahl: still completely unaware of their son's work as a confidential infor