The parents of Lauren Spierer, the Indiana University student who has been missing since last June, reflected on a year of anguish in an interview on NBC's "Today" show Friday morning.Spierer has been missing since the early-morning hours of June 3, 2011, when she was last seen walking toward her apartment building after a night of partying with friends. Special Section: Lauren Spierer Bloomington police said Thursday that they have investigated more than 2,500 tips and that two to three credible tips a week are still coming to them.Months of intense searches have trailed off, but Spierer's family is just as committed to finding out what happened to their daughter as they were on day one of the search."We could have never imagined still, a year later, not having the answers that we desperately want," said Rebecca Spierer, Lauren's sister. "We're leaning on each other and just doing the best we can."The family has repeatedly said that it believes there are people who have answers who have not come forward. It has focused on those who were with Lauren on the night of her disappearance.Investigators believe Lauren was intoxicated and may have needed medical help."The people that were with her that night really did nothing to help her, and that's part of the tragedy here," said Robert Spierer, Lauren's father. "We believe the events would have been completely different if somebody reached out, called for help, taken her to a hospital, taken some kind of action.""We're aware of the fact that Lauren was not in great shape. The idea that Lauren was on the floor of her apartment building, steps away from her apartment, and she could have been taken home and was not is unconscionable," said Charlene Spierer, Lauren's mother.The Spierers are still frustrated by what they believe is a lack of cooperation from those who were with Lauren."In the days immediately after Lauren's disappearance, the people that were with her or had some knowledge of the events of the evening did speak to police," Robert Spierer said. "Shortly thereafter, everyone lawyered up. The lines of communication became either nonexistent or severely limited. To this day, many of those people have not taken police polygraphs, which is what we've asked for from the beginning."The Spierers said their frustration stems from not knowing what happened to Lauren and the inability to narrow the possibilities."We are in constant communication with the Bloomington Police Department, but they do not share any of the specific investigative information, which they have," Charlene Spierer said.The Spierers have said they don't believe their daughter is still alive."You always have hope, but after a year, I don't think it's likely," Charlene Spierer said, her voice quivering."You have to be realistic as parents," Robert Spierer said. "It's an indescribable position to be in. You always have that small element of hope, but as time goes by, you become more and more realistic."The Spierers stressed that they had been in frequent contact with their daughter."Either Charlene or I spoke to Lauren every single day," Robert Spierer said. "We had the communication, but there's just so much you can do. Hopefully, the kids make the right choices."The Spierers have pushed for laws that would shield those who take someone to a hospital during a night of partying from prosecution."You go to any of these college towns and you will find underage drinking going on in these bars, including Kilroy's, which is where Lauren was the night she disappeared," Spierer said. "If other states, like Indiana, passed this lifeline law, which allows people who are with someone who needs help to contact police, take them to a hospital and not be subject to prosecution, those are the kinds of things we need to do to try to make things better."IU Dean of Students Pete Goldsmith and Hillel Center Rabbi Sue Silberberg are holding a remembrance ceremony Friday at noon at the Hillel Center.Bloomington police asked anyone with information to call them at 812-339-4477 or email firstname.lastname@example.org.