Teresa Youngblut, 21, faces federal charges in the death of US border patrol agent David Maland during a January 20 shootout in Vermont. The gun used in the incident links to a double murder in Pennsylvania, with connections to California killings. Police are investigating several individuals, including Jack LaSota and Maximilian Snyder, with ties to these cases. Youngblut’s attorney has not commented, and a detention hearing is scheduled for Thursday.