STONE MOUNTAIN, Ga. -- Vernell Davis thinks almost daily about the last time she saw her daughter alive. It's an image that haunts her nearly as much as her daughter's death itself.

"She was looking at me through the side glass of the police car," Davis remembered. "I had no idea that was going to be the last impression in my mind and my heart, that I wasn't gonna see Shantell again."

28-year-old Shantell Johnson was arrested in the early morning hours of March 5, 2013 and booked into the DeKalb County Jail for driving on a suspended license.

By 1:30pm the next day, Johnson was dead. A guard found her lying on the bottom bunk in her cell, face up and unresponsive.

The DeKalb County Medical Examiner's office ruled her death due to "indeterminable natural causes."

"I just felt something wasn't right about that," Davis said. "I need to know more."

Last week, nearly two years after her daughter's death, Davis filed a lawsuit against DeKalb County Sheriff's Office, individually naming former Sheriff Thomas Brown and nearly two dozen other people, many of whom worked at the jail.

Through an open records request, 11Alive News obtained the internal investigation report conducted by the DeKalb County Office of Professional Standards. In the nearly 150 page report, the final investigation found no violation of policy, except to say the officers who found Johnson in her cell did not immediately administer aid.

But in her lawsuit, Davis claims the jail ignored her daughter's medical issues. Johnson underwent major surgery four months before her arrest, the lawsuit claims, and had complained about vomiting and pain prior to her arrest.

Then, on March 5th, while in DeKalb County custody, Davis claims her daughter complained three times of pain and rang an emergency buzzer in her cell, but was never seen by a doctor.

Of the 22 witness statements included in the internal report from the jail, none of them mention Johnson complaining of medical issues.

However, the medical examiner's report lists Johnson had made "complaint(s) to other inmate of feeling unwell." According to testimony in the sheriff's office internal report, on the day she was found dead, guards completed their routine rounds (with one check delayed by a meeting); in none of the cases did the officer ask Johnson directly if she was ok, asking her cell mate instead.

"She was a human being. No matter why a person was arrested, they still deserve to be treated as a human."