Given the following context:  Ash Mattley, a doctor in a small village deep in the jungles of Borneo, is approached by another scientist, Carl Wessinger regarding his studies of an enzyme found in a rare beetle. With the aid of Mattley and a group of natives, Wessinger secures several of the beetles, but then betrays his team and leaves them behind in a cave. Later, Wessinger uncovers a fossil in the jungle, but the natives in his new team fall in fear and worship before the deceased creature, which they call "Balakai." Two years later, Mattley's clinic is beset by a series of gruesome murders in the jungle. The natives attribute the killings to Balakai, who is an ancient myth in the area. Mattley is enlisted by Claire Sommers, a CIA agent, to find Wessinger. The government had been monitoring Wessinger's activities in the jungle after he began working for them, but the doctor had recently fallen off radar, and Sommers reveals she has been sent to track him down. Together with Matzu, a boy whose sister was one of the victims, they set out into the jungle. Mattley does not initially believe that Balakai is real, but Sommers eventually tells him that the CIA was funding Wessinger's research into the fossil, leading him to change his mind.  answer the following question:  What is the last name of the person to whom Sommers reveals the CIA link to Wessinger?
A:
Mattley