June 8, 2011 -- The search for missing Indiana University student Lauren Spierer was expanded today beyond the campus town of Bloomington as her parents pleaded for her suspected abductor to come forward "if you have a shred of decency."
Spierer, 20, disappeared five days ago when she left a sports bar to walk back to her apartment. The pint-sized student weighs less than 100 pounds and is 4-foot-11.
"We will continue to concentrate searches in the same area, but we also, with the help of the National Center [for Missing and Exploited Children], want to spread these searches out," said Lt. Bill Parker from the Bloomington Police Department.
Search efforts will be expanded beyond the city limits of Bloomington, police said. Police believe foul play is involved in the student's disappearance, but there are no suspects.
"We're going to continue to get interviews of all associates and acquaintances," Parker said. "We're working on polygraphs now."
Spierer was last seen at about 4:30 a.m. on Friday morning walking to her apartment. She was spotted walking barefoot just three blocks from her home.
Police said that a male acquaintance from the bar watched from a distance as she walked part of the way home. He returned to the bar once he felt she was safely on her way, police said.
Surveillance footage from her apartment at Smallwood Plaza shows that she never came home. Her keys were found a block away from where she was last seen, but there have been no other traces of the missing student.
The parents of -Spierer, have traveled from New York to aid in the searches. This morning, they made an emotional plea on "Good Morning America" for their daughter's safe return.
"To the person that has Lauren or that knows where Lauren is, if you have a shred of decency, you have to come forward. Lauren is a beautiful, wonderful girl," said mom Charlene Spierer on GMA.
A troubling sign for the family is that Spierer left her cell phone behind at the bar, something she never does.
"It's not typical of her to leave her cell phone anywhere…it's really an attachment, really an extension of your hand," said Charlene Spierer. "She was pretty careful. She grew up in Manhattan and Westchester [New York] and it wouldn't be very typical of her to kind of strike out on her own."
Her father, Robert Spierer, described her as a "street smart kid."
Bloomington police served a search warrant at Spierer's apartment complex on Tuesday night. They seized computers and computer discs that they hope might provide some lead in the student's disappearance.
Surveillance video shows Spierer at the apartment complex at around 2:40 a.m., nearly two hours before she disappeared.
"[She] was in the building for 10 minutes or so. She did not go to her apartment. She and the acquaintance that was with her came back out," Parker said.
Making time even more crucial is Spierer's dangerous heart condition. She has Long QT Syndrome, an irregular heartbeat.
"What can happen is…your heart doesn't recover quickly enough between beats and you lose oxygen and it can result in your death," said Charlene Spierer.
The blonde good natured student had just finished her sophomore year at the university. She is taking a summer class before heading back to New York to intern with Anthropologie. She is an apparel and merchandising major.
Friends describe Spierer as good natured. She and her sister once volunteered with Habitat for Humanity, raising money to plant trees in Israel.
On a video from the trip, a smiling Spierer says, "We just want to thank all of our friends and family who donated to our fundraising."
Today, her father thanked the hundreds of volunteers and friends helping search for their daughter.
Lauren Spierer Not first Missing Indiana University Student
Among the volunteers is a father who knows Robert Spierer's pain all too well. Lauren isn't the first Indiana University student to go missing. In 2000, 19-year-old Jill Behrman disappeared while on a bike ride. Behrman's father, Eric Behrman, has been helping search for Spierer. His daughter's skeletal remains were found three years later and John R. Myers II was charged later that year in her death. He's serving a 65-year sentence in her death.
Robert Spierer said that he and his wife will meet with the mayor of Bloomington and president of Indiana University to discuss the search today. The family is also meeting with police this morning to learn the latest on their investigation.
"Lauren is a beautiful, wonderful girl," said Charlene Spierer. "To that one person, the one person that has the answer to this mystery and this puzzle, bring Lauren back. Let us know where she is. Take her to a hospital. Let us have her back."
She was last seen wearing long, back stretch pants, a white shirt, and no shoes. A website in Indiana has been set up to organize volunteers and the family is asking that any tip be reported to the Bloomington Police Department at (812) 339-4477.
ABC News' Christina Ng and the Associated Press contributed to this report.