Evidence from an autopsy on Sandra Bland, the black woman found hanging dead in a Texas jail days after a traffic stop, supports the medical examiner's initial ruling of suicide, a county prosecutor told reporters on Thursday.

The preliminary results also found high levels of marijuana in Bland's system, although officials are seeking additional tests to confirm when and how much she might have smoked or swallowed, Waller County Assistant District Attorney Warren Diepraam said.

"The evidence that we reviewed up to this point supports those findings," he said of the initial suicide ruling.