SAN FRANCISCO — A valuable cello stolen from a San Francisco school Sunday was found leaning unattended Tuesday against house door to the War Memorial Opera House, police said.

The Bubenreuth cello, worth about $10,000, was reportedly stolen by two suspects from an unlocked storage locker at 50 Oak St. between 2 and 6 p.m., Officer Carlos Manfredi said. A substantial reward was offered for its safe return.

About 11:55 p.m. Tuesday, a security officer found an instrument leaning against a door of the War Memorial Opera House on Van Ness Ave. and held it for safekeeping, police said. The officer saw a news report about the stolen cello Wednesday morning and told security personnel, who promptly contacted police and school officials.

The instrument was identified as the stolen cello and has been returned to its owner, 23-year-old Adam Young, police said.

“We are very pleased that Adam Young’s cello has been recovered,” Conservatory of Music spokesman Sam Smith said. “It was his most valuable possession and he had no immediate way to replace it.”

Young works as a street musician at the Montgomery BART station and also has a quartet that performs his original compositions in the city’s Castro District, Smith said.

Sheet music for those compositions had been in his cello case and was also recovered with the instrument, which Young has been playing for more than a decade, according to Smith.

Two people were recorded on surveillance video walking into the school and carrying away the cello. They are described as a white 25- to 30-year-old man about 6 feet 1 inch tall and 180 pounds with dirty blonde hair; and a similarly aged female with a thin build, about 5 feet 7 inches tall and 120 pounds with black hair. The pair are not believed to be connected or familiar with the school.

Anyone with information about this case may contact Inspector Brian Danker at 415-614-3463.

Bay City News Service contributed to this report.

Contact Erin Ivie at 925-847-2122. Follow her at Twitter.com/erin_ivie.