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.

Here are four new details emerging in the bizarre and tragic shooting of U.S. Border Patrol Agent David "Chris" Maland in Vermont on Inauguration Day, including the killers' link to a "violent transgender commune.

As the sprawling investigation unfolds, here’s an overview of the key figures involved and their alleged connections.