Confidential Informants: Rachel Hoffman, 23, was caught by police with five ounces of marijuana and a few ecstasy and Valium pills. The authorities offered her a deal: they wouldn't charge her for a crime that could send her to jail, they said, if she helped law enforcement bring down some bigger dealers. With no undercover experience, she agreed to become a confidential informant. She was murdered in the course of a drug deal she did under law enforcement direction. Hoffman's story is part of a Lesley Stahl investigation into the controversial use of young, small-time drug dealers as untrained undercover informants in the war on drugs.Bonobos: In one of nature's bitter ironies, the most peaceful primate on Earth is being driven to extinction by human behavior. In Democratic Republic of Congo, the only place where bonobos are found, Anderson Cooper visits a preserve that cares for the abandoned young of these great apes, which are treated like human babies by the people who care for them.The Spy Among Us: Jack Barsky held a job at some of the top corporations in America and lived a seemingly normal life as a father and husband -- all while spying for the Soviet Union in the last days of the Cold War.