>> the left photograph is pablo aybar. the right photograph is seth. >> melissa monroe had also seen seth and pablo together at casey's bar on the night of the murders. >> i saw them at casey's on the sunday, well, saturday night, sunday morning. i talked to them when i was on the dance floor. seth kept asking me to dance. >> you had all of these witnesses that corroborated and connected seth and pablo aybar to mr. butch casey, the te k-9 gun, and his car. >> seth, a high school dropout with a previous robbery to his name, soon learned he was wanted for murder. >> i actually seen all this stuff in the newspaper. they want to question me about a triple murder. they had a description of my car in there. if you know his whereabouts, please contact us. >> seth decided to turn himself in. >> because i didn't commit this crime. i mean, what person in their right mind's going to turn theirself in, knowing that you did a triple murder? >> seth claimed innocence. but when detectives asked him where he was on the night of the murders

not guilty doesn't mean innocent. >> seth's co-defendant, pablo aybar, is still on death row.to seth that raised questions for the victim's family. >> there's this handwritten letter that's full of rage from pablo aybar. it basically tells him, you're not a victim. man up. take responsibility for your actions. >> for deborah buoy, the letter and the video of the crime can only mean one thing. >> i know that seth penalver is a murderer. he may pretend with anybody else that he's talking to and tell whatever story and thump whatever bible he wants to bring in, but that man is a cold-blooded murderer, and he may be acquitted, and he may be free, but he is guilty. >>> on this episode of "death row stories," executions around the cotry go horribly wron >> it was clear something was not right. >> he looked like he was trying to get up off the gurney. >> you could see spasm go through his body. >> but when secrets emerge about government executions -- >> you've got people carrying cash in the night across state lines. they want to create the aura that everything is smooth. >> -- the