The set of 24 ‘mystery boulders’ installed along Clinton Park — a two-block alley that runs between Dolores and Valencia, parallel to Duboce — are no longer a mystery, as a few residents of the street have copped to placing them there in an effort to deter homeless people from sleeping on the sidewalks.

San Francisco’s Clinton Park has generated some controversy in the past week after 24 large rocks were installed on a sidewalk along the street in an attempt to prevent unsheltered people from crashing there. The genesis of these rocks was originally a mystery, with the district’s supervisor Rafael Mandelman telling the Chronicle, “We don’t know who put them in, but it wasn’t the city.”

And it was not the city. KTVU quotes a neighborhood resident who says, "A bunch of my neighbors, we all chipped in a few hundred dollars and I guess this is what they came up with.”

The rocks, seen above, have been on the Clinton Park sidewalks for about two weeks, according to a Hoodline tipster. Coalition on Homelessness policy director Sam Lew, who posted the above images, tells Hoodline that the money spent on the rocks could have been spent on “real solutions like housing, mental health services, and shelter.” She notes the city has used similar boulders to discourage encampments in other parts of the city.

For their part, the Department of Public Works said Tuesday they had no idea who installed the rocks. “We really don’t know how the boulders got here," DPW spokesperson Rachel Gordon of told NBC Bay Area. "It’s possible they could be deemed illegal dumping; they could be there without a permit. There are definitely scenarios we’re looking at."

Lew disputes the assessment that DPW was not involved, tweeting Tuesday morning that “we saw DPW workers placing boulders there (not removing them) with a city-owned vehicle.”

Gordon also told the Chronicle's Phil Matier that whoever installed the boulders "knew what they were doing" and put them all in the so-called "furniture zone" of the sidewalk, where utility boxes and other objects are permitted. The boulders aren't obstructing the actual walkway and "do not appear to be posing any tripping hazards," Gordon said.

We should note that not everyone on the street is on board with these ‘rocks against homelessness,’ and very few supporters of the rocks were willing to give their name on the record. One angry resident did complain anonymously to the Chronicle that people were “openly dealing drugs” and “yelling and screaming at 3 in the morning and openly flashing weapons.”

But for all of the effort, money, and resulting controversy around these boulders, it’s hard to see how they would prevent drug dealing or late-night racket. They may indeed stop people from sleeping on that sidewalk, or they might not; there is still plenty of available room on the walkway. With more than 200 complaints to San Francisco’s 311 call center on just one block of Clinton Park, though, you can see why residents got the idea for rocks in their heads.

Related: Trump Plans To Tell SF It Has a Homeless Problem [SFist]

Image: @samklew via Twitter