John Whittlesey was an American anthropologist who worked at the New York Museum of Natural History. With Edward Maxwell, he was co-leader of the 1987 Maxwell/Whittlesey Expedition in search of the lost Kothoga Tribe of Brazil's Upper Xingú rainforest. Whittlesey disappeared in the jungle after sending back several crates full of important artifacts to the museum and was presumed dead.
At the end of Relic it was discovered that Whittlesey had not died, but had been forced by the Kothoga to drink an extract of the Mbwun Lily which transformed him into a horrible creature also called Mbwun. Whittlesey lived near the Kothoga until their land was razed for mining by the Brazilian government and then, addicted to the now-extinct Mbwun Lily, followed the trail of his artifacts (which were packed in Mbwun Lily fibers) back to the United States and eventually to the New York Museum of Natural History.
In New York, Whittlesey/Mbwun inhabited the rarely-visited subbasement of the museum and began killing museum employees and visitors who ventured into out-of-the-way areas at night. After several killings, Mbwun was finally stopped by Margo Green and FBI Special Agent Aloysius Pendergast.
After Mbwun was killed, the Whittlesey/Mbwun connection was established by a necklace found in Mbwun's Lair. The necklace contained a talisman, a gold arrow overlaid by a silver arrow, and was a family heirloom that Whittlesey he had worn since childhood. It appeared that, even after his transformation, Whittlesey held onto the necklace and brought it back with him from Brazil.
Pendergast, Frock, and Margo Green missed the significance of the necklace and believed that Mbwun had simply killed Whittlesey. Only Greg Kawakita, who left the museum shortly after the events of Relic, discovered the truth. Kawakita began synthesizing a drug from the Mbwun Lily, which he called Glaze.
See Also: Mbwun
In Reliquary, Whittlesey's first name is given as Julian.