On March 9, 2018, Berkeley painter Kevin Keaney opened his inbox to find a message that would be welcomed by most unknown artists.

The email was from a respected art dealer out of Santa Cruz who had been trying to reach Keaney for weeks. He’d purchased several of Keaney’s paintings, he wrote, and wanted to talk more about them.

But there was a problem: Keaney had never marketed his work or sold any of it in bulk. Until that moment he’d assumed his pieces were safely stowed away in a rented storage unit in San Francisco. It held decades of an artist’s evolution: from the dreamy, jewel-toned abstracts he created in the late 1990s to the gritty, figurative cityscapes he creates today.

After a phone call with the dealer, Keaney began to piece together a devastating realization: “My entire life has just been sold.”

Keaney, 57, began renting a storage unit in December 2016. The unit’s owners at Army Street Mini Storage in San Francisco’s Dogpatch neighborhood received automatic monthly payments from Keaney’s debit card. Keaney vaguely recalls getting something in the mail from them around November 2017, but figured it was just a formality, because the funds were drawn directly from his account.

In hindsight, it’s easy to see what went wrong. Around that time Keaney had replaced his battered debit card with a new one and didn’t think to notify the storage facility of its new number.

Micah Marinero, a front-desk employee at Army Street, said unpaid units are liquidated after three months. Before that happens, he said, Army Street will attempt to call and mail and then call alternative numbers to warn renters that their belongings are facing auction if they don’t settle up.

“We do everything we can to contact them,” Marinero said.

There’s about one auction per month, Marinero said, usually of belongings from a space rented by someone who’s died or has too many problems to deal with the situation.

Keaney joined this unenviable list on Feb. 23, 2018, when, unknown to him, a lifetime of his artwork — 225 paintings, drawings, prints, collages, journals and sculptures — as well as an extensive library, discography, a surfboard and even love letters from his ex-wife were sold to a stranger.

The very next day, Anthony McNaught was running late to the Santa Cruz flea market. An art dealer in the area with more than 7,000 paintings in stock, McNaught made a habit of perusing the wares there. Many of the vendors catered to dealers, collectors and gallery owners.

As McNaught browsed the booths, he came upon a large trove of oil paintings, mostly abstracts with a vibrant palette, all by the same artist.

“You can tell that he works fast, almost feverishly sometimes, and I like that translation of action into the image,” McNaught said. “On a good day he’s a great artist.”

The booth’s vendor, who made a living procuring property at storage and container sales, was already ecstatic. He told McNaught most of his lot had been snapped up by other dealers earlier in the day.

“You missed it,” McNaught recalled the man telling him. “It was a feeding frenzy.”

McNaught said he purchased the remaining pieces for a “very reasonable” price. Later in the day he tracked down some of the other dealers who had brought Keaney’s art. But no one had heard of the “K. Keaney” who’d signed the paintings, nor did they know how his body of work found its way to a flea market.

Something about the situation didn’t sit right with McNaught. It was possible, he thought, that the artist was dead or had moved on from this body of work. But the series of paintings felt somehow incomplete, he said, and “really had the feel of an active artist.”

“I just wanted to make sure that we were squeaky clean on acquisition,” he said. “That it wasn’t somebody’s body of work that they were attached to; that they’d been dispossessed of against their will.”

Keaney is the first to admit he has no online presence. Soft-spoken and perhaps modest to a fault, Keaney, who works as a landscaper, said he’s been “shy” about marketing his artwork. Over the years, he’s sold some pieces to landscaping clients. He’s always wanted to sell his work, but attributes his resistance issues of “self-acceptance that’s a part of any artist’s psyche.”

So when McNaught’s assistant, Megan Crane, was tasked with tracking down the mystery artist K. Keaney, it required considerable sleuthing. She managed to identify Keaney’s full name after finding an old web page for a pop-up gallery he’d created with another artist in 2016 at the Stable Cafe in San Francisco.

That other artist, Carla Caletti, put McNaught in touch with Keaney.

It was after midnight when Keaney first read McNaught’s email. He waited until the next morning to begin researching McNaught online. A sense of dread washed over him when he realized the email’s author was a legitimate art dealer.

“As soon as he told me he had bought some of my art, I knew something bad had happened,” Keaney said.

Keaney and McNaught talked over the phone, and Keaney made arrangements to go to Santa Cruz and try to salvage what he could.

McNaught hadn’t acquired the work that was most important to Keaney and said he offered the artist what he wanted back for the price he’d paid for it. Ultimately, Keaney said, he got back only the love letters and journals from McNaught, who pointed him to the other dealers who purchased his art at the flea market that day.

Overall, Keaney said, McNaught was more than fair about the process, and he remains grateful that McNaught tracked him down. He set out to find the rest of the pieces, particularly those in a new series he’d begun.

“It was a breakthrough, and these were the first pieces in that leap forward,” he said. “I had to get them back.”

Keaney visited another dealer in the North Bay and explained his situation. The dealer asked for $2,000, which Keaney forked over. But he’s had little luck recovering much more.

“The guy who bought my lot didn’t want to meet me,” Keaney said. “He’s afraid.”

Of the more than 225 pieces of artwork he lost in the auction, Keaney has gotten just eight paintings back.

It’s “brutal thinking about them,” he said.

Seven of Keaney’s abstracts and two figurative paintings are still for sale on McNaught’s website, 1stdibs.com, listing for $425 to $7,500. It look Keaney a few months before he could even bear to look at them.

In recent interviews over coffee and at his new Berkeley studio, Keaney said he’s mostly put the devastating chapter behind him.

“I just want to emphasize something — I don’t feel like a victim at all,” he said. “I f—ed up. And I’d been lazy, and this was the consequence of that.”

But the experience had an unexpected effect on him, he said. For years, he’d been plotting a way to give up his landscaping job and pursue his passion full time.

“I had all this art in a black space that I wasn’t really sharing with anyone,” he said. “The way that it was subsequently released from that space ... I mean, a painful learning experience, but truly one that felt like a light bulb.”

It also provided a jolt of confidence. Veteran art dealers were fighting over his work. In their conversations, McNaught told Keaney he wouldn’t have reached out to him if he didn’t think he had so much talent.

Inside Keaney’s new studio, a cozy space near the railroad tracks in West Berkeley, splashes of blood red, canary yellow and warm turquoise intersperse with photo collages of San Francisco cityscapes — “a rough sort of depiction of urban reality” as Keaney calls it.

The studio itself was partly a product of his ordeal, Keaney said. It made him realize he needed a space to nurture his craft and serve as a showroom. In December, he held his first open studio. He’s working on developing an online presence, and is also in touch with a few galleries, hoping to get a show in the next six months.

Ultimately, Keaney said, his loss closed a circle.

“I had this experience ... and whatever you want to call it, fate or bad luck, forced me to come to grips with the fact that I was neglecting a really important part of my practice,” he said. “This is cool, being able to show this work.”

Megan Cassidy is a San Francisco Chronicle staff writer. Email: megan.cassidy@sfchronicle.com Twitter: @meganrcassidy