Joy Pierce and Bruce Beresford-Redman: Photo of an Alleged Mistress

According to Mexican authorities, Bruce Beresford-Redman is the only suspect in the recent murder of his wife.

Earlier this month, the body of the former TV producer's wife, Monica, turned up in a Cancun sewer located outside a luxury hotel where the couple had been staying. It's sad, disturbing stuff.

On April 8, Beresford-Redman was arrested and released by local police. He isn't allowed to leave the country, as officials await DNA results.

A couple days after this horrifying incident, the victim's sister alleged that Bruce had been having an affair, and sources later identited this mistress as Joy Pierce. She and Beresford-Redman worked together on a few television projects.

TMZ has uncovered a photo of Bruce and Joy, taken last summer. It doesn't prove anything, but it doesn't help Beresford-Redman's case, either...