Given the following context:

Astronomer Cyrus Layton is working late one night on his new airplane design in his observatory. He witnesses what he believes is a meteorite landing in the far distance. He contacts his niece Sheila and asks her to bring Craig Foster to the observatory to help analyze his discovery; he then sets out to search for the meteorite crater. Layton instead discovers a crashed spaceship; the ship's pilot emerges and explains that he is from the planet Mars.
Mistakenly thinking the alien is friendly, Layton takes him back to the observatory. Once there the Martian, calling himself "The Purple Monster," wishes to see Layton's designs for the new airplane/spaceship. He proudly shows the alien his designs until the alien explains that he is now stealing them, to build a spaceship for himself to fly back to Mars, where a fleet of the ships will then be used invade the Earth. When Dr. Layton objects, the Martian murders him with a weapon that emits a "carbo-oxide" gas, which kills instantly. The alien then transforms into a ghost and takes over Dr Layton's body. Doing so fools the astronomer's niece Sheila and criminologist Craig Foster, both of whom work with Dr. Layton's foundation, which is responsible for commissioning the spaceship project.
Inhabiting Dr. Layton allows the Martian to witness the unrelated theft of the plans by a gangster named Garrett. The Martian convinces Garrett and his gang to aid in the invasion plot. With the criminals' help the alien begins building the spaceship. Eventually, however, the Martian's efforts at pretending to be Dr Layton fall apart, and Foster and Sheila realize what is happening. A series of action scenes show the pair trying to figure out and stop whatever the alien is doing on Earth. Craig and Sheila constantly battle the Purple Monster's henchmen, who use mind-control poisons, carjackings, and even a booby-trapped vacant lot to dispose of Craig and Sheila.

answer the following question:

What is the first name of the person that helps the niece of the astronomer battle the alien? 

Craig