The preliminary results also found marijuana in Bland's system, though officials are seeking additional tests to confirm that finding, Waller County Assistant District Attorney Warren Diepraam said.
Bland was pulled over on July 10 near Prairie View, Texas, northwest of Houston, for failing to signal a lane change. After the incident escalated into an altercation between her and the trooper, Bland was taken into custody and charged with assaulting an officer. She was found hanging in her jail cell on July 13 with a plastic trash bag around her neck.
An attorney for the Bland family, Cannon Lambert, before Diepraam's press conference said the family wanted a second autopsy conducted.
"The family's confidence is shaken by the continued discrepancies that are surfacing," Lambert said in an email.
Bland's body was returned to the Chicago area, where she lived, on Wednesday in preparation for a funeral on Saturday.
Waller County Sheriff Glenn Smith, whose office operates the jail where Bland died, told Reuters on Wednesday that the jailers on duty when Bland was admitted felt she was not a suicide risk based on their observations and her statement on the questionnaire that she was not depressed at the time.
The jail where Bland died was cited three days after her death by the Texas Commission on Jail Standards for failing to complete visual face-to-face observations of inmates every 60 minutes as required by state regulations.
Bland was being held alone in a cell designed for up to five women when she was found dead.