incredible. trace gallagher, live with more on this story. hi, trace. >> reporter: gretchen, apparently this wasn't just a spur of the moment decision to kill mom and dad. one of the brothers says he's been scheming to murder his parents since he was 11 years old. christopher ervin is now 22 and along with his 17-year-old brother, cameron, police say they admitted to drugging their parents, stabbing dad, beating mom, trying to suffocate both of them with a plastic bag and attempting to light the house on fire while the gas line was leaking inside. police believe the sons likely would have succeeded if the father hadn't distracted them long enough for mom to sneak away and call 911. listen. >> i heard them say that they put xanax in our drinks. that's why we were so sleepily. we didn't understand why we were so sleepily, but that's why. >> how do you know it was xanax? >> that's what they said after they started attacking us. that's what they said. >> okay. please, please hurry.