SAN JOSE — In the noisy cluster of tents and tarps beneath a cloverleaf interchange south of downtown, they call the perpetrator “Machete Jack” because of what happens at homeless camps when nobody’s watching.

In at least three locations in recent weeks, homeless people have found their tents sliced and rendered useless, their bicycle tires slashed and their scant belongings ripped apart.

“It’s almost like a hate crime,” said Karl Crepsac of the vandalism that occurred at his illegal campsite off Race Street late last month. “It’s tough enough to live out here … But slashing my tires? I see no reason for that at all — that’s how I get around.”

Who is this Machete Jack? Nobody seems to know. And the incidents have not been reported to police. Advocates say there’s an ingrained distrust of authority among the homeless and reluctance to report such crimes against their property.

Crepsac and other homeless people whose belongings have been sliced, as well as some of the advocates who help them, allege the culprit works for the California Department of Transportation, which manages the state freeway rights-of-way where many camp illegally.

That’s an assertion that Caltrans, as well as the California Highway Patrol, which accompanies the agency’s workers when they clear out campsites, deny.

“The CHP works with us side by side, and they have not indicated anything has gone wrong,” said Caltrans spokesman Bernard Walik. “There’s been no formal claim against us. From a common sense perspective, the CHP would see something like that if it were happening.”

CHP Officer Ross Lee said state troopers are “unaware of any incidents of ‘tent slashing’ or other claimed property being destroyed.”

Caltrans said its workers follow a procedure when it comes to clearing camps: They post a written 72-hour warning that they’re coming, then allow the homeless to gather their most needed possessions when they’re ousted. The agency stores items of value that the homeless leave behind for up to 90 days.

Anthony King, a homeless advocate with Silicon Valley Debug who is helping Crepsac file a claim with Caltrans, sent an email narrative to the area supervisor, but was told in a response that the agency did nothing of the sort.

“At no time was there any weapon of any kind present or slashing of any Tents per CHP and our Caltrans Supervisor,” wrote Caltrans maintenance Superintendent Arthur De La Cerda.

Whoever cut up the camping gear, it’s left the homeless shaken.

“It’s really jarring, really scary,” said one homeless woman who identified herself only as Monica and lives with her boyfriend in a redwood grove near the Children’s Discovery Museum. “We were just gone for a little while, and some psycho comes through here and does this?”

Scott Halvorson had his $200 tent — a gift he said he received last Christmas — carved up like a pumpkin in the same vandalism attack that victimized Crepsac. Halvorson, Crepsac and Phil Russell had their remaining possessions cleared from the site about a week later, and all understand that comes with the territory of illegal camping. But they don’t expect vandalism that leaves them unexpectedly exposed to the elements.

“This is basically what we call home for now,” Crepsac said, holding up a shredded shell of a tent. “This you can’t fix. There’s positively no way. This is just so that you can’t use this again, and I don’t see a reason why … someone would maliciously vandalize our home.”

Teresa Chapman, who works at the Sobrato Center for Nonprofits next to the site where Crepsac and Halvorson had their tents slashed, came outside out of concern for her neighbors the day after the incident to see what had happened. She said they shouldn’t be treated poorly because of where they live.

“We’re all equal as human beings and all deserve to be respected,” she said. “Their presence here makes a statement that more help is needed. This world is hurting, and people don’t need to be any more injured than the circumstances have already injured them.”

Contact Eric Kurhi at 408-920-5852. Follow him at Twitter.com/erickurhi.