An oddly worded e-mail was the first sign of something amiss at Los Angeles firm Gipson Hoffman & Pancione. It didn’t read like the messages the firm’s attorneys usually sent each other — didn’t pass the “smell test.”

His suspicions raised, the recipient, associate Gregory Fayer, picked up the phone and discovered that the colleague who supposedly sent the e-mail knew nothing of it. Other attorneys at the firm also received the bogus e-mail, which was eventually traced to China — where Gipson Hoffman is litigating a $2.2 billion copyright infringement suit against the government. Fayer was well aware that cyberattackers often use fake e-mail messages to break into computer networks.