"Who could do this and walk away and just continue their lives?" Kristy Bottle asks herself and anyone who may be able to make sense of the horrific death of her beloved sister Sandra. Because how could the universe be so cruel?

Hour by hour, questions Kristy fears may never be answered crowd her mind: 

"Was the killer drinking?

Was it someone with a police record?

Do the images of that night replay in his mind over and over as they do for Sandra's loved ones?

Does he think about Sandra's children and what they're going through?"

THE CASE

"YOU KNOW WHO KILLED ME" prompts the billboard that's positioned just feet from where 37-year-old Sandra Lee Loepp was struck and killed in December of 2012. She had gone out with friends in Washington Township, Mich. – the outskirts of Detroit –  to a local bar. She and her friends met there and then took a party bus to and from a restaurant in Detroit. HNGN has learned that later that night she and her husband got into an argument and he stormed off, intending to walk home. Family members say Sandra followed shortly thereafter, her friends unaware she had chosen to walk the mile and a half home.

But she never made it. 

Approximately a half hour after beginning her walk - around 1 a.m. – an unknown car driver struck Loepp with incredible force, the vehicle dragging her body approximately 600 feet. Someone in the car – the driver or a passenger - pulled her shattered body out from under the vehicle. Then the car just drove off, abandoning the mother of five to die alone.

It wasn't until later that morning, after a passerby found Sandra's body in the parking lot of a mobile home community, that anyone knew she was missing. Now they were being told she was dead, killed in a horrific manner.

"Her injuries were so significant that we didn't have the option to see her or have an open casket," says Kristy Bottle, now 37, who is Sandra's little sister, the baby of seven siblings. Sandra was the second youngest.

Sandra was strikingly beautiful – tall and thin and always dressed to the nines. But her family says her inner beauty was really what made her special. "She had the biggest heart, always doing for others and putting herself and her happiness last," says Kristy. "She was also very determined; you never wanted to tell her something couldn't be done, because she would go the extra mile to prove it could be done, especially if it meant bringing joy to someone's life."

"Our family has been pretty shielded from the extent and details of her injuries. Everyone of us has imagined it, though," says Kristy. Sadly, Kristy says that Sandra's husband's grief has manifested in cutting off communication with his wife's family.

The neighborhood and community immediately rallied - posting fliers, hanging signs, raising funds for billboards and helping raise nearly $13,000 for the reward fund. The community also helped her three sons and two stepdaughters. 

"We do our best to be there for her kids, but no one can ever replace that relationship they had with her," says Kristy. "She was a terrific mom who only wanted what was best for her kids. We need to find her killer."

"Whoever did this is a monster without a conscience," says a law enforcement official familiar with the case. He needs to remain anonymous because he's not authorized to talk about it publicly. "To just leave her for dead is despicable."

THE INVESTIGATION

From the get-go, police have said that the case has been a difficult one. 

"There is no physical evidence that will lead us to a suspect," says Det. Sgt. Melissa Stevens. "We will solve it, but it's going to take a tip from the public."

Now, HNGN has learned that police have followed more than 70 leads. They have run down a number of names that surfaced and a number of potential vehicles that may have been involved. But, so far, nothing has panned out. 

"Every tip that has come in has brought us hope. There were a couple that seemed so promising that we thought, 'This is it! We finally got the person,' only to be brought back at square one," Kristy says.

Police believe Sandra was crushed by the car and died quickly. Investigators believe the car had to have been traveling at a high rate of speed – 60 mph within a residential speed zone – for such an accident to have created such injuries. Police found pieces of Sandra's hair at the impact point and all the way to the place where she was abandoned, additional evidence that she was dragged underneath the vehicle.

One thing investigators know for certain is that the vehicle must have sustained significant front-end damage. What's more, police believe the suspected driver may have been drinking and may have been from the area or visiting someplace familiar in the area. The reason: the driver was traveling on a local access road and not on the highway that runs alongside it.

Detectives have spoken to dozens of people who were in the area that night and contacted a number of collision shop owners, asking them to notify police about anyone seeking repair work that might have been caused during the hit-and-run.

"Thinking of what she would do is what has driven us to keep this going," says Kristy. "We know if this happened to anyone of us, she'd push to search for answers and wouldn't stop until they were found. We want as many people as possible to be familiar with her story so when the person or persons responsible finally slip up and say something, the people around them will be familiar with her story and be able to make the connection."

HNGN has learned that other hit-and-run accidents in the area have been solved after tips were called in, even from tipsters who thought they were calling about Sandra's case.

THE FAMILY TAKES TO FACEBOOK

Kristy has set up a Facebook page for members of the community to talk about the case and to drum up leads.

She believes the killer could even be following the developments on Facebook. "I would think they would try and keep tabs on the progress of the investigation."  

"We pray that one day we will get 'the call' – the one telling us there is an arrest being made." Kristy says.

POSTSCRIPT

To help, please visit the Justice for Sandra Loepp Facebook page. Tipsters can provide information anonymously by calling Crime Stoppers at 1-800-SPEAK-UP (1-800-773-2587). 

Jon Leiberman is an Emmy award-winning investigative correspondent, host, producer, victim advocate and author. He recently wrote the book "Whitey On Trial," about the mob. In addition to contributing to HNGN, he is a contributor to "Snapped" on Oxygen and various other television shows. Leiberman is a former correspondent for "America's Most Wanted." Follow him on Twitter @reporterjon.