They told Katie Couric in December 2012 that they were "stonewalled" by Spierer's friends, and that they do not believe their daughter's disappearance was a "random abduction."
"We have these boys that were there that night that clammed up, shut down, lawyered up," Robert Spierer said on "Katie."
"I'm frustrated and I'm angry at this point. We've been stonewalled, to some extent, by the last people to see Lauren, and despite their claims of doing whatever they could do, the fact of the matter is they refused to meet with us except for one of the boys," he said.
Most of the men refused to take police polygraph tests and instead took "independent polygraphs."
Since Lauren's disappearance, multiple discoveries of remains have been reported in the area. None were identified as Lauren's.
Police have said the search for Spierer is still an active investigation. The Spierer family has retained its own private investigators to follow up on tips and leads.