QUAKERTOWN, Pa. (AP) -- The owner of a home-based chemical sales company has been arrested in connection with a series of mysterious explosions the past three months in suburban Philadelphia, authorities said Thursday.

Bucks County District Attorney Matt Weintraub said 30-year-old David Surman Jr. had been arrested on charges of weapons of mass destruction, reckless endangerment, possession of methamphetamines and other counts after search warrants were executed at his home and his business. Weintraub shared a picture during a news conference of an 18-inch bomb with four fuses that he said was ready to be detonated.

He declined to speculate how much damage it could have caused.

"What we have found are multiple explosive devices in this residence," he said pointing to a picture of the largest bomb. "This is what we believe to be a large bomb that was capable of mass destruction."

Federal agents earlier detonated a number of devices at one of the locations.

Weintraub says the charges are related to the material seized Thursday, and investigators were sending materials to a lab in Quantico, Va., to see if they could be forensically linked to nearly 30 explosions and seven confirmed blast sites over the last two months.

About three dozen explosions have been reported in Bucks County since early April, typically in the middle of the night. No one has been hurt.

Weintraub said the incidents had been linked to a person nicknamed the "mad Upper Bucks Bomber."

On June 14, a municipal worker on a ride-on mower was cutting grass along a road when he ran over something that exploded, leaving a 2-foot-deep crater.

Along with pictures of the devices and chemicals found Thursday, Weintraub showed photos of collages and drawings created by Surman. In one, created from cutout graphics and photos, he pasted his picture and his girlfriend's inside an SUV driving away from an explosion with a large cat and dog in the foreground. Another hand drawn note included a swastika, but Weintraub said he would not speculate whether Surman belonged to a hate group.

"These speak for themselves," he said.

Weintraub said the investigation involving the FBI and federal ATF agents is ongoing and more charges might be possible depending on whether forensics link the previous devices and explosions. He said none contained shrapnel that he was aware of.

Weintraub also said the girlfriend, whose name was withheld, was being cooperative and had not been charged.