"I was a little out of my mind, you know, with desperation, and all I wanted to do was find her."

 I understand why Kathy Kupka felt that way: Her younger sister had disappeared, and when police found no sign of her, Kupka suspected her sister had been killed.

 She put up a huge billboard offering a $25,000 reward. Soon, psychics began calling her with messages from beyond -- beyond the credible, that is. They said things like, "I know where your sister is."

 Kupka says she got phone calls urging her to contact Sylvia Browne, one of America's most famous psychics. Browne's Web site says, "Visiting here explains the Meaning of Life." Browne claims that she can talk to the dead and they tell her where they are. So Kupka managed to get on a TV show on a day when Browne was doing her stuff. "I was so super-hopeful," she said. "I was like, oh, that's it, we're definitely going to find her."

 On the show, Browne quickly said Kupka's sister was dead in New Mexico -- and communicating to Browne.

 Back in this world, police investigated Browne's lead. It was a phantom.

 "It was so devastating," Kupka told me. "Desperation makes you do things that reasonable people don't do."

 ABC News asked Browne to talk to us about this. She agreed but then backed out at the last minute. She had told us she solved thousands of cases. But several years ago, a magazine examined 35 of Brown's "cases." It couldn't find proof she'd solved any of them.

 At least Browne didn't ask Kupka for money. Nor did the next psychic Kathy tried, Karl Petry. But he did take her to a hazardous-waste facility and tell her that her sister was inside a manhole.

 Kupka says police checked this lead out, too, and found nothing. Petry says the body must have washed away.

 ABC News went to another psychic, Kathlyn Rhea, who some police officers say has helped them find bodies. Continued...