People could have been killed or seriously injured if a homemade bomb allegedly found in a truck parked on Capitol Hill had exploded, according to an  FBI expert.

FBI agent Daniel Hickey, a prosecution witness, told the D.C. Superior Court Monday that a device found in Michael Gorbey’s truck three weeks after his arrest was “clearly designed to be an anti-personnel weapon” and that “people in close proximity hit by these fragments could be seriously injured and possibly killed.”

He added: “There would be no other reason to combine these components.”

Members of the U.S. Capitol Police bomb squad and the FBI allegedly found the device three weeks after Gorbey’s arrest for approaching the Supreme Court building with a loaded shotgun. The truck was parked on D Street NE, two blocks north of the Russell Senate Office Building.

They say the device consisted of a glass bottle containing 250 BBs taped to a metal canister filled with black gun powder. While the device remained undiscovered, Capitol Police sources said it posed no threat to passers-by because it did not have a fusing system.

After discovering the device, members of the bomb squad rendered it safe. It was then transferred to FBI laboratories for analysis.

Gorbey faces 14 charges, including manufacturing a weapon of mass destruction, and is representing himself in D.C. Superior Court.

Gorbey has argued that the canister found in his car is simply a container of gunpowder that could be purchased in any gun supply store. In his cross-examination, Ohm pointed out that Hickey didn’t know what the device was intended to do, and only examined it after it had been rendered safe by the Capitol Police bomb squad. This split the device open, making it more difficult for Hickey to say with certainty that the device would have caused harm, Ohm suggested.

Lawyers also argued over whether a hole in the container was designed to be a place of entry for a fusing system to detonate the black powder, or was simply created when the device was rendered neutral. Prosecutors argue it was intended to help set off the device, but Hickey, under questioning from Ohm, said that he could not say with certainty that the hole was present before the bomb squad rendered it safe with a high-powered water canon.

Hickey said it was at least possible that the hole could have been made during the process of neutralizing the device, but he said this was unlikely based on his experience as a trained bomb technician.

Capitol Police have come under scrutiny for not finding the device sooner. Rep. Dan Lungren (Calif.), ranking Republican on the House Administration Capitol Security subcommittee, said he was disturbed by the delayed discovery and suggested police had performed only a cursory search of the vehicle.

“The incident in question is certainly a matter of concern and deserves further scrutiny,” said Alison Mills, spokeswoman for Rep. Michael Capuano (D-Mass.), the subcommittee’s chairman. “The Subcommittee on Capitol Security is committed to exploring the circumstances surrounding this particular event in a manner that is sensitive to security considerations. This is precisely the sort of issue that I believe should be addressed in a private setting.”

Capitol Police moved a bomb squad supervisor, present on the initial search of the vehicle, to a less prestigious security detail in the House Office buildings last month in an effort to address the delayed discovery, according to sources.

The prosecution is expected to finish the questioning of its witnesses Tuesday morning, after which Gorbey will begin to call his witnesses. Gorbey’s alleged girlfriend, Amy Toothman, is expected to be among the first called to testify.