hours later, her 12-year-old brother, thomas cogdell, sits in an interrogation room ready to confess.n. he's convinced investigators will soon clear him in the death of his sister kaylee. >> i'm thinking if i just get through this and tell them what they want to hear, i can go home, get done with this. >> we're going to go over the rights with you, make sure you understand what your rights are. >> police read thomas his rights. >> with full knowledge i hereby voluntarily and knowingly agree to answer your questions. do you understand the waiver? >> huh-uh. what's a waiver? >> it simply says that what you're saying, you're doing of your own free will. >> okay. >> the definition they gave was incorrect. he's 12 years old. he does not comprehend what it means to give up a right to an attorney. what happened last night at your house between you and your sister that led up to where we are today? >> she was asleep with the tv still on. so i put the trash bags over her head and i held them there for a few minutes. >> what are you calling a trash bag? >> the walmart bag. the walmart bag over