lucie, florida, tyler hadley's house party is in full swing. 60 teenagers drinking and drugging with t, tyler's older brother ryan away at college. >> one kid was walking around saying, "i smell dead people." other kids had seen some signs of blood, or what could have been blood. the house was a mess. it looked like it had been ransacked. >> reporter: as the night wears down, tyler is growing agitated. >> do you recall him yelling at somebody trying to go back towards the back part of the house? >> yes, i heard him just saying, "get out of the hallway. i don't want anyone in the hallway." >> reporter: how does he seem? >> he seems eager to tell me something, and he's -- wants to take me down the street and talk. >> reporter: so, you guys walk out the house. tell me what happens then. >> he says, "mike, i killed my parents." and i said, "no, you didn't, tyler. shut up." and, he said, "mike, look at the driveway, all the cars are there. my parents are dead. i killed 'em." >> reporter: and then with partying teens still inside the house, tyler tells mike to look for the telltale signs --