Sandra Bland, a 28-year-old African-American who died in police custody three days after being arrested, told a guard she previously attempted suicide, according to the sheriff in Texas.
A coroner’s report said Sandra Bland hanged herself but her family doubt this.
Sandra Bland was arrested on July 10 over a confrontation with a policeman who pulled her over for a traffic offence.
A video of the incident shows the officer appearing to threaten her with a Taser and say: “I will light you up.”
Sheriff Glenn Smith, whose Waller County jail was where Sandra Bland was held, told the AP news agency on July 22 that during the booking process she said she had tried to kill herself in the past .
He said Sandra Bland’s comments were made after she was asked a series of questions that are posed to every person who is detained at the jail in Hempstead, about 60 miles northwest of Houston.
Glenn Smith said another guard also spoke to Sandra Bland. She told him she was upset but not depressed, according to the sheriff, and both jailers insisted she appeared fine at the time.
Sandra Bland was found dead in the cell three days after her arrest and officials say she hanged herself.
Cannon Lambert, the lawyer representing Sandra Bland’s family, said relatives have “no evidence” that she previously attempted suicide and denied she was suffering from depression.
He said the family wanted investigators to get to the bottom of what happened, adding: “Sandy [Bland] was a social activist. Social activists don’t take her own life.”
Cannon Lambert also said the dash cam video of the arrest, which was released by the Texas Department of Public Safety (DPS) on July 22, showed that Sandra Bland’s death “could have easily been avoided”.
In the video, Brian Encinia, a white police officer, is seen issuing a ticket and then asking Sandra Bland to stub out her cigarette, which she refuses.
When the woman refuses to step out of the car, he tries unsuccessfully to pull her out. He then appears to threaten her with a Taser and says the words: “I will light you up.”
Sandra Bland gets out of the car and they move out of vision, but the audio suggests the confrontation becomes physical before more officers arrive.
A number of breaks were spotted in the original video that the DPS posted on to YouTube, prompting many people on social media to question the authenticity of the entire film.
However, a DPS spokesman insisted it had not been edited and that the glitches were a result of a technical error. The original video was later removed and another version was posted online.
Officer Brian Encinia, who has been on the force for just over a year, said he was kicked during the arrest. He has been put on administrative leave.
Texas DPS director Steven McCraw said his officers have “an obligation to exhibit professionalism and be courteous” but that “wasn’t the case in this situation”.
Sandra Bland’s death is one of several under scrutiny in the US in which a black person has died while in police custody.