When Min Jong Shon’s $46,000 viola was stolen from her practice room at the San Francisco Conservatory of Music, she didn’t sit back and wait for the police to recover it. Instead, she banded together with some friends, and used a network of phones and e-mail communications to try to prevent the thief from fencing the instrument. Shon tracked the thief’s movements to various instrument dealers, and eventually recovered the instrument and fingered the culprit on her own. Police were stunned and thrilled, and expect to have the suspect in custody shortly.