MILFORD TOWNSHIP, Pennsylvania -- A lawnmower tripped an explosive device lying in the grass in Pennsylvania Thursday afternoon, causing large explosion.
FBI and ATF agents descended on Brick Tavern Road near Allentown Road in Bucks County around 1 p.m.
Area resident Melissa Pfistner was working in her home, with her children upstairs, when she heard a loud boom and her bookcase fell over.
It turns out a worker was cutting the grass across the street with a tractor-driven mower when his blades struck the explosive device. It left behind a 2-foot wide crater that was about 2.5 inches deep.
Authorities are warning those who live nearby to not walk on uncut grass on the side of the road in case there are other devices.
"It's kinda scary when you got little guys," said Pfister.
Investigators have previously said they believe the rash of explosions in Upper Bucks and Lehigh counties are the work of an unknown culprit.
Another explosion a couple of weeks ago left a 10-foot wide crater that was 1-foot deep along the 1200 block of Lonely Cottage Road in Upper Black Eddy.
There have been upwards of three dozen explosions since the first more than two months ago.
So far, no one has been injured. But Thursday's incident escalated concerns along Brick Tavern Road, and now, officials said there is no more grass mowing until further notice.
"This is terrorism because everybody around here worries every night," said Gary Rosenberger, of Milford Township.
State Police Dublin Barracks are taking the lead in the investigation. No suspects have been named as of this time.
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Lawnmower trips explosive device lying in the grass in Pennsylvania