The story about the boulders of San Francisco took another turn Friday when someone — or several someones — rolled six of the heavy, large rocks from the sidewalk onto the street.

No one appeared to be taking credit for the act, which happened amid criticism that the placement of the boulders on Clinton Park, an alley between Dolores and Valencia streets, was a cruel way to keep homeless people off the street. They’re 2 to 3 feet high and 3 to 4 feet wide and not easy to move.

The boulders appeared on the Clinton Park sidewalk weeks ago, residents say. They were placed anonymously, but neighbors have said that a group of residents raised money to set up boulders to dissuade drug dealing and homeless people.

The rolling of the rocks came a day after a woman, upset by the boulders being placed on the street, offered them for free on Craigslist.

Lauren Hernandez is a San Francisco Chronicle staff writer. Email: lauren.hernandez@sfchronicle.com