HEMPSTEAD, Texas -- The district attorney investigating the death of Sandra Bland says he's bringing in a committee of outside attorneys to review evidence as it's collected.
Waller County District Attorney Elton Mathis said Monday that the panel of lawyers will help his office make decisions based on "credible evidence and not rumors."
Bland, a 28-year-old black woman, died in the county jail after a traffic stop by a white state trooper for failing to use a turn signal escalated into a physical confrontation. Her arrest has gotten international attention and questions about whether she was mistreated due to her race.
Mathis released an initial toxicology report last Monday. Preliminary results show Bland had marijuana in her system, a finding that could be "relevant to her state of mind," assistant district attorney Warren Diepraam has said.
Authorities say Bland hanged herself with a plastic bag on July 13, three days after being pulled over by police in Waller County. Bland, who was from Naperville, Illinois, was in Texas interviewing for a job at nearby Prairie View A&M University, a historically black college from which she graduated in 2009.
"We know for a certainty that before she went into that jail, she was ecstatic," Bland family attorney Cannon Lambert said. "She had left messages with her loved ones and that just does not jive with someone who would take her own life."
Authorities have said the bag was tied to an overhead steel partition of the jail cell where Bland died. The "circular area" of the bag formed by the slipknot was about 6½ inches in diameter, wrote Dr. Sara Doyle, who signed the report.
The report released Friday did not address toxicology, saying only that blood and urine and other specimens have been sent for additional tests. Prosecutors have said final results could take weeks.
Diepraam said there were "approximately 25 to 30 horizontal faint... linear superficial incised wounds" up to an inch long on her body. He said they were likely self-inflicted, weeks earlier.
While Bland's family disputes the notion she was suicidal and suspects foul play was involved in her death, officials released Bland's booking forms that showed she admitted she felt depressed and once attempted suicide.
In an apparent voicemail Bland left for a friend, obtained by Houston station KTRK, Bland also seemed frustrated to be behind bars.
"They got me set at a $5,000 bond. I'm just still at a loss for words about this whole process, how this switching lanes with no signal turned into all of this, I don't even know," Bland apparently said.
Bland's friend, Lavaughn Mosley, told the station it's her voice, but CBS News has not been able to independently verify it.
CBS affiliate KHOU reports friends of Bland say she was an active voice against police brutality and that they believe that's at the heart of the case.
Bland's family flew back to Illinois with her body Wednesday and tried to keep the focus on the actions of the arresting officer, trooper Brian Encinia.
"She was pulled over for something so insignificant and because of an officer who felt like maybe that his ego was bruised. ... When you tell me that you're going to 'light' me up, I feel extremely threatened and concerned, and I'm not going to get out of my car," Bland's sister, Sharon Cooper, said.
Mathis agreed the arrest was troubling.
"When I first saw the dashcam video, I thought ... 'This is not what I want to see out of a law enforcement officer.' And in that same respect ... saw Ms. Bland and would have just wished she would have cooperated," Mathis said.