They started small.
On December 21, twin brothers Caleb and Daniel Tate exploded a mailbox in Pennsylvania's Chester County, authorities say.
Two days later, they set off an improvised explosive device in the woods nearby.
Then, they moved on to bigger targets.
On December 31, the Tates detonated a pipe bomb in an Amish phone shed, an enclosed structure that housed a phone used by multiple Amish families who ban telephones in their homes. A day later, the brothers blew up two more bombs: an IED in an Amish produce shed and another in a shed housing a well pump.
The men, from Cochranville, set off the bombs in the morning. The buildings were unoccupied, but anyone present could have been injured or killed, prosecutors said.
"We live in a world where the thought of bombs exploding around us is a very real fear," Chester County District Attorney Tom Hogan said. "These defendants brought that fear to our region during a two-week crime spree where they detonated multiple IEDs."
Daniel King of Strasburg Township heard a loud boom around midnight local time on the final night of the alleged bombing spree, he told LancasterOnline.
"It was kind of scary," he said.
The next day, King discovered the splintered produce stand where his family sells apples and blueberries in season.
The 22-year-old twins used metal pipes, fuel containers, propane canisters, propane torch tips, and other items to make the bombs, which they detonated in five places - all in a 20km radius.
The brothers set off the bombs after coming home from college: Daniel Tate had just graduated from Pepperdine University in California, and Caleb Tate is a student at Tennessee's Belmont University, their lawyers told Philly.com.
Investigators were able to find the brothers by uncovering security footage that showed three white men at a nearby Walmart shoplifting items related to the explosive devices. They also paid for three containers of Zippo fuel using a debit/credit card linked to Daniel Tate, according to a criminal complaint affidavit. His fingerprint was also recovered from electrical tape left at one of the bombing scenes.
In February, an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives met in California with Daniel Tate, who confessed to making and detonating the bombs at all of the crime scenes while home on Christmas break.
His younger brother, Andrew, had been with him during the bombing spree, but had little involvement in the crimes, he told the agent. Caleb Tate also confessed to the crimes, according to the affidavit.
The brothers are charged with arson by explosion, arson by possession of explosive devices, conspiracy, theft and related charges.