Robert and Charlene Spierer told WNYW, a TV station in their native New York, this week that they believe private investigator Bo Dietl has found new details related to their daughter's case.

Special Section: Lauren Spierer

When asked if Dietl, a former New York City police detective, had found any information that was different from what police had uncovered, Robert Spierer said yes, but declined to share that information.

The 20-year-old was last seen walking in Bloomington in the early morning hours of June 3 after a night of partying with friends.

As Hanukkah begins, her parents told the TV station that the first holiday season without their daughter is emotional.

"You think about, you know, if you sign a card, how do you sign the card?" said Charlene Spierer, weeping. "You think about, you know, wrapping the presents, putting the name on the presents."

Without any solid leads, the Spierers said they don't know what else police can do to advance the case.

"I think they're doing what they can. I don't know what else I could direct them to do, quite frankly," Robert Spierer told the TV station.

The couple said they wish the four men who were among the last to see their daughter would come forward with more information and take a police polygraph test.

"They all have attorneys. None of the people of interest have any obligation to go in and speak with the police department," Charlene Spierer said.

The family said they're still holding out hope someone will share key information that will lead to their daughter.

"There's no words to really describe, for us, it's every moment of everyday, thinking about Lauren, we're holding her with us, we're carrying her and it's... the holidays. Everyday is hard for us because she's such an intergral part of our life," Rebecca Spierer, Lauren's sister, said.

"I'm not naive enough to think that there's not a possibility that we won't find Lauren. There are so many cases of missing people who have not been found," Charlene Spierer said. "I can't imagine that as my life. I'm hopeful that we will find Lauren."