A college professor in Wisconsin was arrested after he allegedly murdered his pregnant girlfriend and her dog and tried getting rid of the evidence by setting her house on fire. Matthew R. Sierra has been arrested on charges of first-degree intentional homicide, first-degree intentional homicide of an unborn child, arson and mistreatment of animals causing death after he was accused of killing Alexis Pickett, according to jail records viewed by Us Weekly. The La Crosse Fire Department responded to the home on November 13 around 3:30 a.m.