here's morales' cameo. >> a bulldog named armando "mousey" morales. >> reporter: back in 2006, moralessharing a federal prison cell for separate crimes. now on the stand, morales makes a stunning allegation -- guandique made a detailed confession to the levy murder. >> his testimony was convincing. he knew certain things. >> reporter: after morales' testimony, guandique is found guilty and sentenced to 60 years in prison. >> the result of this verdict may be guilty, but i have a life sentence of a lost limb missing from our family tree. >> reporter: one of the country's longest ongoing murder mysteries is finally over. or is it? the conviction starts to wobble two years later when the defense discovers that the snitch morales concealed a crucial fact from the jury. he had a history of working with law enforcement. >> knowing those prosecutors, my guess is they had no idea until after the fact about mr. morales' prior cooperation, maybe they should have. >> reporter: honest mistake or not, it's a big enough deal to make some very big news. >> the accused killer is getting a new trial. >

the chandra levy trial, armando morales. >> his face changed completely. it went from this gentle, kind, caring guy, into a look that almost scared me a little. >> reporter: trusting his new friend, morales reveals he's just done 20 years in prison. >> i said, "20 years? you must've almost killed someone to be in for 20 years." and his answer was, "i wish it would've only been one person." >> reporter: here? morales explains he's the key witness in the upcoming retrial of ingmar guandique. while preparing to testify, the government has put him up in the hotel with a cell phone, a room key, and some cash, and strict orders not to blow his cover. what did you think? >> i was intrigued of his involvement, what he knew. >> reporter: she's intrigued enough to continue the odd those close to her. so she makes a fateful decision. babs says that, for her own protection, she begins recording her conversations with morales in the hotel, in the car, even in this storage locker where he's helping her organize her things. this is where you recorded it all, mostly. >> i