She calls it art, proudly signing her urban-influenced sketches and posting photos of them online, like a sort of Banksy in the wild.

The National Park Service calls it criminal.

The agency on Thursday announced it was investigating 21-year-old Casey Nocket’s recent cross-country jaunt during which she allegedly painted faces and sketches on rock formations in as many as 10 national parks, including Rocky Mountain National Park.

The agency, which did not name Nocket, said its investigation spans the nation’s most iconic Western parks. Investigators said the woman’s vandalism was found in Yosemite and Death Valley national parks in California, Crater Lake National Park in Oregon and Zion and Canyonlands parks in Utah. National Parks Traveler on Thursday posted a photo of Nocket’s trademark scribble inside Rocky Mountain National park.

The Park Service was awaiting confirmation of vandalism in Grand Canyon, Sequoia Kings, Joshua Tree and Bryce national parks.

Park officials said in a statement it takes seriously the issue of vandalism, which can be a felony when committed in a national park.

“National parks exist to preserve and protect our nation’s natural, cultural and historic heritage for both current and future generations. Vandalism is a violation of the law, and it also damages and sometimes destroys often irreplaceable treasures that belong to all Americans,” Park Service spokesman Jeffrey Olson said in a statement.

Nocket, who hails from Highland, N.Y., posted her coarse scribbles — sometimes even photos of herself sketching — on her Instagram and Tumblr accounts under the name Creepy-Tings.

After a backpacker posted photos of a Nocket painting along a trail near Yosemite’s Vernal Falls on the website Reddit, the site’s savvy Internet sleuths tracked the photo to Nocket’s social media accounts. Steve Yu, a special agent with the Park Service in Yosemite, saw the post and launched an investigation.

Yu declined to comment when reached Thursday.

The Internet rage grew with Nocket’s apparent lack of remorse.

A painting she posted on her Instagram account of a blue-haired lady on a rock overlooking Oregon’s Crater Lake prodded one of her followers to ask if she was using paint or chalk. Nocket responded that it was acrylic: “I know, I’m a bad person.”

In response to angry posts on her Tumblr site early Thursday, she defended the paintings, saying, “It’s art, not vandalism. I am an artist.”

Nocket’s Instagram account was deleted as of Thursday, but sites like modernhiker.com, which broke the story of the vandalism, were able to post all her Instagram photos, including one of her mid-sketch in Canyonlands.

Nocket’s hubris — posting her crimes online — has enabled investigators as they build a case. And it’s not the first time a Web search has uncovered vandalism of public lands.

The two Boy Scout troop leaders who posted a YouTube video of themselves toppling 170 million-year-old hoodoo rock formations in Utah’s Goblin Valley State Park in 2013 were fined and sentenced to probation this spring.

Casey Schreiner, who on Tuesday posted the Nocket story on modernhiker.com, a site he founded in 2006, said the passionate outcry over Nocket’s paintings likely stems from the “slap on the wrist” earned by the Goblin topplers.

“Everyone seemed pretty mad about that,” Schreiner said. “This is definitely part of a broader problem inside parks of all kinds across the country.”

An online petition at whitehouse.gov had collected more than 2,220 signatures Thursday afternoon, urging authorities to pursue “the most serious charges” and pleading “please don’t allow her to receive a slap.”

Vandal news from national parks was common in 2013, with hoodlums defacing cacti in Saguaro National Park, painting over petroglyphs in Joshua Tree National Park and scribbling graffiti near a popular rock climbing area in Rocky Mountain National Park.

The financially strapped Park Service is struggling to address a growing backlog of deferred maintenance, and the agency recently proposed a fee increase to help offset rising costs.

“When you don’t pay, this is what happens. There are not enough rangers on the trails to patrol and prevent these kinds of things,” said Schreiner, noting that Nocket’s photos indicate most of her scrawlings are just off well-traveled trails.

Ed Nocket said his niece is a “good girl.” While he knew she was touring the West with friends, he said he was not aware when reached Thursday that his niece’s poorly placed paintings had raised such ire.

“She’s got a lot of talent,” he said. “She’s not seeing that she is doing something that is not condoned. She probably has a different approach to it.”