from one of Ammann's long-term trackers. Williams reported on her close encounter, "we could hear them in the trees, about 10 m away, and four suddenly came rushing through the brush towards me. If this had been a mock charge they would have been screaming to intimidate us. These guys were quiet, and they were huge. They were coming in for the kill – but as soon as they saw my face they stopped and disappeared". According to Williams, who claims she learnt Lingala, the local populace classified great apes into two distinct groups. There are the "tree beaters", which disperse high into the trees to stay safe, and easily succumb to the poison arrows used by local hunters. Then there are the "lion killers", which seldom climb trees, are bigger and darker, and are unaffected by the poison arrows. Other reports attribute this statement to Ammann. Williams claimed to have observed three species of chimpanzees, including this new one, during her summer tour. "The unique characteristics they exhibit just don't fit into the other groups of apes", said Williams. The apes, she argued, could be a new species unknown to science, a new subspecies of chimpanzee, or a hybrid of the gorilla and the chimpanzee. "At the very least, we have a unique, isolated chimp culture that's unlike any that's been studied", she said. These and other sensational pronouncements to the media proved controversial, and Williams was subsequently no longer welcome to study the animals with Ammann. Ammann had published a letter in 2003 decrying Williams' unprofessional involvement. Williams vowed to continue without him, making plans for another expedition. Cleve Hicks, a primatologist recruited by Ammann in 2004, stated "genetically, they're not even a subspecies". Mitochondrial DNA resolved from hairs taken from the nests found in 2003 that the chimpanzees belonged to Pan troglodytes schweinfurthii. Williams countered that all these hairs may have contaminated by real chimpanzees or humans, or that the conventional use of mDNA regions discovered in human research as genetic markers was incorrect in primatology, or that the mDNA, which is only transmitted by mothers, would not reflect one-way hybridisation with male gorillas. In 2004, Hicks studied several communities of the chimpanzees approximately 60 km northwest of the town of Bili. Although the apes, including adult males, would surround the humans and display an interest or curiosity in them, somewhat like previous reports, they did not