In December 2004, Wally and Heidi Knerler took their daughter, Annette, and granddaughter, Danielle, on a weeklong cruise to Mexico that Heidi had won in a raffle. The Waukesha, Wis., couple expected to have nothing but fun. The last thing they expected was to return home heartbroken and with a mystery on their hands.
Wally said everything was going great -- right up to the last night of the cruise. That evening, after dinner, they all went to the lounge where Annette and Danielle lit up the stage singing karaoke together -- the Britney Spears' song "Hit Me Baby One More Time."
After the karaoke, Danielle and her grandparents went back to their room to pack. Annette stayed behind but called them to plan for the big event of the evening -- bingo.
"Annette didn't want to miss that, because she won twice in bingo. Small pot, but she won twice. She was very excited," said Heidi.
Bingo started at 10 p.m., and Annette planned to get there early to get a good seat. When the Knerlers arrived, they couldn't find her.
Her parents were immediately concerned. Wally went to look for her in the casino but couldn't find her there either. A short time later, they heard their daughter being paged.
"When we heard that page, I knew something was wrong," said Wally. "My heart just fell ... I panicked. I knew something was wrong."
The Knerlers immediately sought out cruise officials and were told that someone had found their daughter's handbag next to an overturned drink on one of the decks next to the ship's railing. But Annette was nowhere to be found.
Heidi looked at her daughter's purse and noticed something that made her fear Annette might have been attacked.
"I said to Wally, 'Why are all the beads torn off?' " she said.
Wally and Heidi thought that the damaged purse indicated a struggle. Suspecting something bad had happened to his daughter, Wally said he implored ship officials to help.
"And I said, 'Well, are you looking for her?'" Wally recalled. "And they were just like, 'Yeah, we're taking care of things. Everything's OK. We're talking care of things.'"
Fearing precious time was being wasted, the Knerlers decided to search the ship themselves. Danielle searched the area where Annette's purse had been found and made a discovery.
"I saw a whole bunch of black dots all over the deck. And it was her beads [from the purse] scattered all over the deck," Danielle said.
Wally said they also found other possible clues, including a cup with liquid spilling out of it and a pen and bits of paper scattered about -- none of which, they say, had been collected by ship personnel.
Wally then said he called security and insisted they secure the area with crime scene tape.
"I made them do that. I insisted on it, very strongly," he said.
Wally said security didn't seem to have a procedure for gathering evidence or even taking pictures, so the panicked father took his own photos of the possible crime scene.
He also said the ship did not slow down, nor were resuce boats sent out into the water. "It was full speed ahead," Wally said.
Carnival Cruise Line declined "Primetime's" request for an interview, citing a pending lawsuit, but they did send a letter, which noted that it's not uncommon for guests to report that a travel companion is missing.
"In almost all circumstances the guest is eventually located onboard," Carnival wrote.