Sandra Bland's Family Orders Independent Autopsy After Alleged Jail Suicide

— -- The family of Sandra Bland, who died in police custody Monday in Texas, has ordered an independent autopsy to be conducted today, a family attorney told ABC News.

The family expects autopsy results with 48 to 72 hours, family attorney Cannon Lambert said.

"We want to understand how it is that this kind of played out and what will end up ultimately being the cause of death," Lambert said.

While authorities said that Bland, 28, committed suicide, her relatives say she was days away from starting a new job and would never take her own life.

Bland, who lived in the Chicago suburb of Naperville, graduated from Prairie View A&M University and was planning to move back to Texas. She was arrested on July 10 in Prairie View following a routine traffic stop, with authorities alleging that she was "argumentative and uncooperative."

In cell phone video of the arrest that was posted to YouTube, Bland can be heard questioning officers’ tactics, accusing them of slamming her to the ground.

Bland was found dead in her cell three days later.

Waller County District Attorney Elton Mathis said an autopsy found Bland died by asphyxiation and that she used a plastic bag to hang herself from a partition in her cell. He added that although jail video didn't show what went on in Bland's cell, it showed no one went in or out of it from the time she was placed there until a jailer found her unconscious.

A prosecutor said Thursday that he will present the findings of a Texas Rangers' investigation to a grand jury. The FBI is also investigating the circumstances surrounding Bland's death.

Bland previously discussed her struggle with depression in a video posted to Facebook in March.

"I want you guys to know it's a daily struggle. It's a daily test," she said. "Depression is nothing but the devil. It's a way of mind and it's a way of thinking."

The Associated Press contributed to this report.