Friday marked five years since Lauren Spierer, an Edgemont native, was last seen after a night out near Indiana University.

The 20-year-old sophomore was still at school finishing a summer course on June 3, 2011. The next day, her parents Robert and Charlene received a phone call that she had gone missing.

After months of searching to no avail, the family turned to private investigation firm Bo Dietl and Associates in New York City. Michael Ciravolo, who spoke to News 12 about the investigation for the first time Friday, has run down hundreds of tips and interviewed witnesses, some of whom he said never even told their story to Bloomington police.

"We don't leave any stones unturned," said Ciravolo.

On June 3, 2011 at 2:27 a.m., Spierer was seen leaving Kilroy's Sports Bar with fellow IU student Corey Rossman. Her cellphone and shoes were later found in the bar.

Rossman has claimed through his attorney that he was assaulted and doesn't remember much of what happened that night. He was interviewed by police in the days following her disappearance.

"Corey Rossman, the boy who was out with her, has never given us an interview and adamantly refuses to do so," said Ciravolo.

Spierer was last seen on surveillance video leaving another friend's home, Jay Rosenbaum. Her keys were found in an alley she may have taken to get there.

Rosenbaum, Rossman and his roommate Mike Beth were the last to see Spierer alive before she vanished. The family filed a civil suit against them, claiming negligence resulting in her disappearance and possibly even her death.

It said Lauren was disoriented, incapacitated, slurring her speech and highly intoxicated.

The suit also suggested Rosenbaum allowed her to leave on her own at 4:30 a.m.

A judge later dismissed the lawsuit. The men have never spoken publicly about it.

"I just don't understand why the people who were with Lauren in her last hours...wouldn't do everything they possibly can to help us," Charlene Spierer told News 12 in 2011.

Ciravolo said the family will never give up looking for their daughter, and neither will he. He told News 12 that they are looking at someone in prison to see if there is a possible connection to the Spierer case. They have also received tips through social media.

The investigator said Bloomington police have remained tight-lipped and don't often share information. Authorities in Bloomington told News 12 that Lauren's case is a top priority and is not considered a cold case.

"This is the one that I wake up to every morning and go to sleep with every night," said Ciravolo. "I know we're going to bring Lauren home, I just cannot tell you when."

After repeated requests, the Spierer family declined to be interviewed for this story. Charlene Spierer did release a statement online saying in part, "Going through this nightmare, I consider all the possibilities of what could have been done to Lauren after she took her last breath and I can only hope that her suffering was short."