Trying to find the name of the US cop show.....

Basically a sister is shown a picture of her brother as proof he's still alive and is a vietnam POW and some guy is conning people to pay money to rescue them - however, the hero(es) discover that the photo has just been mocked up in a particular part of a zoo. It could be an A team episode? Or a film, or a detective show. 

Does this ring any bells with anyone??