It’s been three years since Sandra Bland died under suspicious circumstances in a Texas jail, and ever since then her mother, Geneva Reed-Veal, has been fighting for victims of police abuse.

Reed-Veal has traveled throughout the country with other “mothers of the movement,” supporting families who have lost loved ones at the hands of police and lending her voice to the movement for change.

Later this year, a documentary about Bland’s life and death will premiere on HBO—but Reed-Veal said it was extremely difficult for her to watch it at the Tribeca Film Festival premiere last April.

“I’m sitting there at Tribeca watching with everyone else. Then I see my baby in the cell, lying on the ground, all these numbers around her,” she told the Chicago Sun-Times. “In these three years, I had never seen the crime scene, the photo of cell 95, where she was found. I’d refused.”

“And seeing that thing tore me up,” Reed-Veal admitted. “I left out of a side door, went back to the hotel and sank into extreme depression.”

Though Reed-Veal will be at the Chicago premiere of Say Her Name, the documentary about her daughter’s life, seeing Bland’s lifeless body on screen for the first time was a shock to the still-grieving mother.

“My head was thrown right back to 2015,” she continued. “I was in the hotel, balled up and crying for three days. When I finally got myself together, I told them, ‘You all never told me you would use her real body. Do you understand that I have never seen that photo? Do you understand that I never wanted to see that?’ They were very sorry.’

Though Reed-Veal said Say Her Name was “one of the best things” she’s seen about her daughter “because a lot of it is in her own words,” Reed-Veal also clarified that she won’t be seeing the film again.

“I told them I can’t watch that movie anymore for the rest of the screenings,” she said. “It’s too hard for me.”

Say Her Name: The Life and Death of Sandra Bland is slated to premiere on HBO in December.