The killings of a Border Patrol agent in Vermont last week, a state’s witness in California, and a pair of senior citizens in Pennsylvania all appear to be linked to a fringe group of West Coast vegan activists and artificial intelligence theorists.

Teresa Youngblut, 21, faces federal firearms charges in the Jan. 20 death of U.S. Border Patrol Agent David Maland, and police and court records have shed some light on connections to killings in othe

The weapon that killed Agent David Maland last week in northern Vermont was bought by a person of interest in a double murder two years ago in Delaware County, state police say.