Solve It: The Mystery of Lauren Spierer Indiana coed vanishes without a trace. Can you help crack the case?

 -- Indiana University student Lauren Spierer went out for a night of partying and was never seen or heard from again. In the early hours of June 3, 2011, the petite 4’11” coed with blonde hair and blue eyes seemingly vanished without a trace.

But former FBI agent Brad Garrett believes somebody knows something about what happened to Lauren the night she disappeared. With over 30 years of experience in law enforcement, Garrett has solved many high-profile cases by connecting with the people in the community, developing their information and using his unique crime-solving skills to find the bad guys. He is now using the same approach via social media.

“Nobody simply vanishes. Someone heard something or saw something that night which might seem insignificant, but it could be an important piece of the puzzle,” said Garrett, an ABC News consultant. “With the new series ‘Solve It,’ we’re hoping someone will comment or post what they know online, and help solve the mystery of what happened to Lauren.”

“We Will Never Stop Searching”

Lauren, 20, who was studying fashion merchandising at Indiana University, went to a party with friends the night she disappeared. For her parents Charlene and Robert, and her sister Rebecca, trying to find out what happened that night has been a constant, heartbreaking search for answers.

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“We haven’t stopped searching, we will never stop searching. Lauren will have her day,” they wrote in a recent post on the Lauren Spierer Family Updates Facebook page. “Loving you always, Lauren. Forever in our hearts. Just as determined as day one.”

The Spierers filed a negligence lawsuit against Jason Rosenbaum, Corey Rossman and Mike Beth, the men last seen with Lauren the night she disappeared.

The Spierers claimed Lauren’s disappearance resulted from her being given alcohol by Rossman and Rosenbaum when she was already intoxicated, and that all three men owed Lauren a “duty of care.” Rosenbaum, Rossman and Beth all retained lawyers and have maintained that they had nothing to do with her disappearance.

Lauren’s Story

The events of Thursday evening, June 2 into Friday, June 3, unfolded in a six- to eight-block radius of Bloomington, Indiana. The following is what police and private investigators believe, based on surveillance images and witness statements.

10 p.m. - Party at 11th & Morton Sts.

On Thursday evening, June 2, Lauren and her friend David Rohn left her apartment at Smallwood Plaza on 8th and North College to attend a pregame party at Jason Rosenbaum’s apartment on 11th and Morton St. Rosenbaum had texted Lauren earlier in the day inviting her over. According to the Spierer’s lawsuit, Lauren was served several drinks at the party.

Lauren and an acquaintance, Corey Rossman, left the pregame party to go to Rossman’s apartment in the same complex. Rossman’s roommate, Mike Beth, says Lauren was visibly intoxicated, yet Rossman still encouraged Lauren to join him at a nearby bar, the lawsuit alleges.

1:45 a.m. - Kilroy’s Sports Bar

Rossman and Lauren arrived at Kilroy’s Sports Bar on Walnut St. Lauren was served more drinks and became increasingly intoxicated. According to the lawsuit, at least one witness observed Lauren needing assistance from Rossman to stand straight and walk. Lauren left her shoes and cell phone at the bar.

2:30 a.m. - Lauren Returns Home

Investigators say surveillance video showed Rossman and Lauren heading back to Lauren’s apartment at Smallwood Plaza. Spierer was observed by multiple individuals in a distressed, incoherent and nonresponsive state near the elevator on the fifth floor, where her apartment was located, the lawsuit says. Rossman was confronted by one of these individuals, a male later identified as Zach Oakes. According to investigators, Rossman argued with him, and Oakes punched him in the face.

2:42 a.m. Lauren Leaves Smallwood Plaza

Lauren and Rossman left Smallwood Plaza. Video surveillance showed Lauren stumbling as Rossman helped her walk along a debris-strewn path. According to investigators, Lauren, who was barefoot and intoxicated, dropped her keys and ID in the alley.

Lauren and Rossman made it back to his apartment at 11th and Morton. According to what roommate Beth told investigators, Rossman was unsteady, then fell and vomited on the stairway up to his bedroom.

Beth suggested Lauren stay on the couch and go home in the morning, but she refused, according to her parents’ lawsuit. Beth called Jay Rosenbaum for help, and Lauren went back to Rosenbaum's apartment. According to Rosenbaum's statements, he also encouraged Lauren to stay over, but Lauren again refused.

4:30 a.m. Lauren Walks Into the Night

Rosenbaum says that Lauren decided to leave, and he watched from his small balcony as she walked to the corner of 11th and North College. He told investigators that he thought he saw someone in the shadows intercept her. Lauren was never seen again, and surveillance cameras never captured any images of her on the route home.

Lauren’s boyfriend, Jesse Wolff, reported Lauren missing after sending her text messages and getting a reply from an employee at Kilroy’s, where she had left her phone.

The Search for Lauren

In the days and weeks that followed, investigators and students scoured Bloomington for any sign of Lauren. Despite a lengthy investigation and more than 2,500 tips, nobody has been arrested or named a suspect in Lauren’s disappearance.

Charlene and Robert Spierer filed a negligence lawsuit against Rossman, Rosenbaum and Beth, all of whom insisted they had nothing to do with her disappearance. Rosenbaum passed a polygraph test, according to his lawyer, and Beth was dropped from the suit.

The court eventually dismissed the claims against Rosenbaum and Rossman because the Speirers could not show what happened to Lauren, nor that her intoxication caused her disappearance. In October 2014, the Spierers appealed the dismissal. They have refused to comment for fear of jeopardizing the case, yet their private investigator says they remain haunted by not knowing what happened to Lauren.

“You have a family here who lives every day not knowing what happened to their beautiful daughter,” investigator Michael Ciravolo told ABC News. “They deserve closure. We need a break. We need that phone to ring. Someone out there knows something.”

Do you know something? Did you see something? If so, comment here or post on ABCNews Facebook, contact Brad Garrett directly at bradley.j.garrett@abc.com, tweet him @BradInvestigate, or call him at 202 222-6148. You can choose to remain anonymous, but please let us know how to contact you if we need to follow up.

Thanks for helping Solve It.