48 Hours Mystery: Is the murder case the against former reality TV producer Bruce Beresford-Redman falling apart?

(CBS) CANCUN, Mexico - After seven months in a violent, chaotic Mexican prison while on trial for his wife's murder, former reality TV producer Bruce Beresford-Redman hopes the prosecutor's case falls apart before he does.

And he may have reason to be optimistic.

You can hear his hope - and his desperation - in a new video message he recorded for his son Alec and daughter Camilla during a prison visit with "48 Hours" just last summer.

"Hi guys. I miss you very much," says a haggard Beresford-Redman, speaking directly to his children. "I love you. Hopefully I'm coming home soon."

Whether he's allowed to come home anytime soon and whether he really killed his wife Monica during a 2010 vacation to Cancun are two different questions.

Mexican authorities have admitted that much of the physical evidence in the case is contaminated or lost. Some government witnesses even failed to show up when they were due in court. Others have actually undercut the prosecutor's circumstantial case, though the prosecution insists there's still enough evidence for a conviction.

"We have to work with what we have," says the chief prosecutor.

"I am looking around, waiting for someone to stand up and say, 'Okay, well, we've got the wrong guy,'" Beresford-Redman tells "48 Hours" correspondent Troy Roberts. "You know, 'let's get him the hell out of there.' And that doesn't happen. It absolutely floors me."

With his fate hanging in the balance, life in prison has improved for the former Survivor producer. After discovering he'd granted "48 Hours" a world-exclusive interview last winter, authorities moved him from a segregation cell to the general population, where he shares a cell with four other men.

He's got a lot more freedom of movement now. But there are also new risks. To avoid being ambushed by the thieves, killers and drug traffickers in his overcrowded cellblock, Beresford-Redman says he spends his time outside, in the dilapidated gym, the dusty library or sitting in the prison yard with his back against the wall.

As his trial inches along - despite lost evidence, missing witnesses and appeals from his lawyers - Beresford-Redman knows he may end up in exactly that position.

"If I'm convicted, I'm facing 30 years in a Mexican prison," he says.

Josh Yager is a producer for "48 Hours Mystery."