A San Francisco woman is pleading for help after, she says, witnesses told her that her brother is being tortured so violently in a Saudi prison it could end up killing him, CBS San Francisco reports.

Areej Sadhan said Abdul Sadhan, 35, was arrested in March of 2018 at his office in Saudi Arabia. He works for the Red Crescent, the Red Cross of the Muslim world. Areej Sadhan believes her brother was imprisoned by the secret police who, she said, didn't explain why they took him or where he was going.

She said he "disappeared."

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"They refer to his case as an 'enforced disappearance,"' Areej said. "When someone gets kidnapped or detained and you can't communicate with them at all, they just vanish."

Areej is an American citizen, as is her mother. They live in the Bay Area. But her brother isn't.

After graduating from Notre Dame de Namur University in Belmont, California, he immediately left the United States because his student visa ran out, Areej said.

Areej Sadhan and Abdul Sadhan CBS San Francisco

Areej said she's worried because she got an anonymous call from someone who claims to have seen Abdul in a prison getting severely tortured.

"They told me he is in danger and that he might die from the torture," Areej said. "And that's when I got very, very scared."

Sadhan said she is hoping media coverage and social media saturation will help get her brother released.

University of San Francisco professor Stephen Zunes, PhD, said the Saudi regime has always been oppressive and isn't usually swayed by media appeals or bad publicity.

But, given the murder of journalist Jamal Khashoggi and recent negative reactions to other arrests of dissidents, Zunes said it's possible public pressure could make a difference in Abdul Sadhan's case.

"Those of us in the Bay Area have a connection with his sister here," Zunes said. "We have a number of influential members of Congress, including the speaker of the House. We can play a particular role in bringing attention to this case and put the kind of pressure that needs to happen."

Areej said family members have reached out to Speaker Nancy Pelosi's office, but a staffer told them there wasn't much they could do because Abdul isn't an American citizen.

CBS San Francisco reached out to Pelosi's office as well as the Saudi Consolate in Los Angeles, but the station hasn't received a return call.