(BLOOMINGTON) - The parents of missing Indiana University student Lauren Spierer told Katie Couric they're frustrated.
Robert and Charlene Spierer appeared on "Katie" on Monday on RTV6 as part of an episode about the families of missing children.
Robert Spierer is frustrated with the friends of his 20-year-old daughter Lauren.
"I'm angry. We've been stonewalled, to some extent, by the last people to see Lauren," he said. "Despite their claims of doing whatever they could do, the fact of the matter is they refuse to meet with us, except for one of the boys, they refuse to take a police polygraph, which we feel is important for a number of reasons, one of which is to help narrow down the field of people who really know what happened to her that night."
Lauren was last seen walking toward her Bloomington apartment the morning of June 3, 2011.
Charlene Spierer, says their biggest dilemma is not knowing if it was a random abduction.
"For me personally, I think the events of the evening leave me with thinking it was someone who knew Lauren," Charlene said.
She broke down in tears recalling when she and her husband visited the area where their daughter was last seen.
"There were girls walking home alone, as if her disappearance didn't make a difference," Charlene Spierer said, her voice breaking.
Robert Spierer told Couric he holds on to the slimmest of hope that his daughter might be out there somewhere alive. But he said he's adjusted his expectations.
"I understand that Lauren may no longer be with us," he said. "We ache for her. We want to bring her home."
Monday's episode also featured "America's Most Wanted" host John Walsh, whose 6-year-old son was abducted and killed in 1981.
Walsh told Couric, it's not knowing where their child is or what happened to their child that is the most difficult for parents.
"Very rarely do kids come back, that's a fact," he said. "But every now and then you get a Jaycee Dugard."
Anyone with information about Spierer's case is asked to call the Bloomington Police Department Tipline at 812-339-4477 or the family's private detective firm, Beau Dietl & Associates, at 800-777-9366.
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