American Heiress: The Wild Saga of the Kidnapping, Crimes and Trial of Patty Hearst by Jeffrey Toobin:
After Steven Weed moved out of the Hearst family mansion, he continued his quixotic, independent investigation of the kidnapping. In early April, Weed tried to make connections in the radical exile community, hoping to find a country that might grant asylum to the SLA, if they freed Patricia. One of his contacts suggested that Régis Debray, the originator of the foco theory (whose books had been found in the Concord house), might be willing to help. As a bonus, Debray had known the original Tania and could speak about her character and motivations. Weed’s acquaintance called the singer Joan Baez, a friend of Debray’s, who agreed to contact the Marxist theoretician, who was living in Mexico. Debray indicated some interest in trying to help. Weed then ran the idea by Randy Hearst.
“We need a goddamn South American revolutionary mixed up in this thing like a hole in the head,” Randy replied.