Ugandan officials are negotiating for the release of a California woman and a local tour driver who were kidnapped at gunpoint in a wildlife park on Tuesday. The search has widened as well, CBS reports. Kimberly Sue Endicott and Jean-Paul Mirgene Remezo were taken by four men in Queen Elizabeth National Park. The kidnappers have demanded a ransom of $500,000. They've been using Endicott's phone in the negotiations, and she's been on the call at least daily to show that she's alive. The park is on the border with the Congo, and the border has been sealed, police said. Endicott, 56, is an esthetician in Costa Mesa, friends told ABC7, and had been looking forward to the safari. "One of her big dreams was to go see the gorillas," a neighbor said. Four other tourists in her group were left unharmed. (More Uganda stories.)