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.

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.

The Vermont Border Patrol agent murdered when he stopped a migrant near the northern border has been identified as David C. Maland, The Post has learned. An agency veteran of nearly a decade,