Someone is soaking homeless people in San Francisco with buckets of water, and it's a move many are calling cruel.

People who live and work at 20th and Bryant streets say when homeless people are camped out on the sidewalk, someone is getting up on the roofs of adjacent buildings and dumping buckets of water on them. Some neighbors say they want to know who it is so they can tell them to stop.

Video shows a person dumping a bucket of water off the roof of a two-story building Saturday onto a homeless person below.

Rich Caraballo says he was shocked when he realized someone was soaking the woman and her belongings intentionally.

"She was sopping wet," Caraballo said. "At first, I thought, all right just a weird coincidence. Then it happened a second time."

A man who works in the building at 20th and Bryant says he saw the same thing happen last week.

"I was outside with colleague, witnessed ton of water come down and land on person," he said.

Witnesses say they don't know who has access to the roof. They believe the person responsible is drenching people so they move along.

The Coalition on Homelessness says it's not unusual for people living on the street to be targets.

"There is the dehumanization of a population that's poor," coalition spokeswoman Jennifer Friedenbach said. "Grouping together, stereotyping leads to acts of hatred against them."

Police say if the victim files a report, it could be investigated as misdemeanor battery. For now, a Twitter user is offering a $1,000 reward for information that identifies the person responsible.