The two co-founders of the local bands Dirty Cello and San Francisco Yiddish Combo were robbed of their musical instruments in San Francisco Tuesday night, but a strong community effort and the ingenious play of a Good Samaritan helped recover the valuable cello and guitar about 15 hours after they went missing.

Santa Rosa Symphony cellist Rebecca Roudman and her husband, guitarist Jason Eckl, had gone from a teaching gig straight to a David Crosby concert at the Castro Theatre, parking their car with the instruments covered in the back. When they went to check on them at intermission, they found their car window smashed and Roudman’s Luis and Clark carbon fiber cello and Jason’s Rainsong guitar gone, along with the cases and two carbon fiber bows.

All told, the equipment was worth about $12,000, Roudman said by phone from their Novato home. And they had three upcoming concerts to play this weekend, including a Dirty Cello concert in San Rafael on Friday night. (Roudman and Eckl were profiled in J. in July.)

Police were called, but the response was slow. Where else to turn but Facebook? Roudman quickly posted the distressing news, asking her online community to keep a watch out for anyone selling or fencing the stolen instruments. Some of her friends reposted to FindMyGearCalifornia, a public Facebook group set up by musicians to aid in the recovery of lost or stolen musical instruments.

Early the next morning while she was filling out a police report, Roudman got a message from a man who said he thought he had located her property: Two individuals were trying to sell them on a site called Letgo.com. “I think these are yours,” the man wrote. What’s more, he had already arranged to meet the sellers in Oakland to look at the goods. He texted Roudman his location.

While Roudman and Eckl were battling traffic to hurry to the meeting spot, the Good Samaritan, Allan Harrell (online name “Alex Richard”), met the sellers in a McDonald’s parking lot and deployed a number of creative ruses to stall the purchase, including taking the young man and woman to breakfast. The pair wanted to sell what they described as two guitars for $1,300.

“We don’t think they even opened the case. They thought my cello was a guitar,” Roudman said.

Once they arrived and identified the stolen goods as theirs, Roudman said Eckl, who is all of 5-foot-4 (but a former gymnast and Central Valley farm boy), rushed over, grabbed the instruments out of the sellers’ hands and swung them onto his back while he shouted accusations at the pair. “I bet your mother doesn’t even love you!” was one barb. The thieves fled.

Roudman described the quick-thinking Harrell, who had recognized the signs of a suspicious seller, as “a nice person who you’d want to be friends with right away.” She publicly thanked him and her entire online community, especially @findmygearcalifornia.

“Lessons learned: Both friends on social media and kindhearted strangers like Alex really saved the day. Also, the community of musicians, music appreciators and general kindhearted people of the Bay Area far outweigh the power of two petty thieves,” she wrote.

A police investigation is underway.

Only a few days before, on Nov. 3, the San Francisco Yiddish Combo had performed at Congregation Shomrei Torah in Santa Rosa. The concert, one week after the Oct. 27 synagogue shooting in Pittsburgh, had filled the musicians with a deep sense of responsibility.

“For us to perform that weekend — we knew we had a job to do,” Roudman said. “We let people marinate in the music and maybe helped them not think about the tragedy for a few hours and just have a good time.”

Congregants came up to the band after the performance and told them, “That was just what we needed this week.”

Dirty Cello performs at 7:30 p.m. Friday, Nov. 9 at Key Tea in San Rafael, and at 2 p.m. Sunday, Nov. 11 at the Willits Community Center.