Given it is bird hunting season in VT right now I would first check for theout of state hunters.
That is no doubt the likeliest explanation. I don't know if local LE feels there is another possibility or not. The report said "it has people in southwestern VT nervous because of the recent sniper shootings in Maryland". Typical.
The Sierra Times article asked about other unexplained shootings around the country so I threw it in.
The people reporting FBI and ATF agents coming around "asking questions about their guns" has me more worried than a rash of sniper shootings.