DALLAS — A black woman who authorities said hanged herself in a Texas jail had posted an online video earlier this year saying she was suffering from “a little bit of depression,” though family and friends say the 28-year-old gave no indication she was distraught enough to contemplate suicide.

As Sandra Bland’s family and friends press for details of what happened, 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, who was from the Chicago suburb of Naperville, was moving to Texas to work at Prairie View A&M University, the historically black college from which she graduated in 2009. She was arrested on July 10 in Prairie View following a traffic stop, and authorities say she hanged herself Monday morning in a Waller County Jail cell in nearby Hempstead, about 60 miles northwest of Houston.

Her death comes amid increased national scrutiny of police after a series of high-profile cases in which blacks have been killed by officers or died while in custody. Social media posts have questioned the official account of her death.

Bland had posted a video to her Facebook page on March 1 in which she said that she was suffering from “a little bit of depression as well as PTSD,” or post-traumatic stress disorder. She did not explain the cause of the PTSD.