Michael Lewis was worried Sam Bankman-Fried being in a room with his own dog was an accident waiting to happen

• FTX cofounder Sam Bankman-Fried did not know how to instruct his guard dog to kill on command, according to Michael Lewis' new book.
• "When Sam was in a room with the dog, it always felt as if some accident was waiting to happen," Lewis wrote in the book.
• His book on Bankman-Fried, "Going Infinite: The Rise and Fall of a New Tycoon," was released on Tuesday.

FTX cofounder Sam Bankman-Fried did not know how to instruct his guard dog to kill on command, according to Michael Lewis' biography on the fallen crypto titan.

The dog — a German shepherd named Sandor — was purchased by Bankman-Fried's parents for security reasons, Lewis wrote in the book. It had been trained to attack on command — in German.

Bankman-Fried's parents learned the attack commands, but not the former CEO of FTX.