WAKEFIELD, Mass. (AP) — The software engineer accused of gunning down seven co-workers stashed ammunition and a semiautomatic with a sniper scope in his office and bomb-making material in his home, authorities said Wednesday.

Michael M. McDermott, 42, pleaded innocent Wednesday to seven counts of murder and was ordered held without bail.

Defense attorney Kevin Reddington made no argument for bail. He said his client had been undergoing psychiatric treatment and asked that McDermott be held where he would be able to continue taking medication.

Wearing an orange jail jumpsuit and a bulletproof vest, the manacled and bearded McDermott stood impassively in court, his bushy dark hair draped over his shoulders.

He looked around the courtroom frequently as prosecutor Tom O'Reilly described Tuesday's carnage: The shooter blasted through the offices of Edgewater Technology with 37 rounds from a semiautomatic rifle and several from a shotgun, striking workers in their heads and backs as they tried to flee.

"There was very little, if any, missed shots. Most of the wounds went through and through the bodies," O'Reilly said.

"One of (the victims) was underneath his desk. He had been shot numerous times. Another was a young lady slumped over her keyboard of her computer. She had been shot in the back of the head," O'Reilly said.

Police found McDermott sitting silently in the reception area, a body nearby, his weapons within reach. He was arrested without gunfire.

Officers who searched McDermott's work area Wednesday at the Internet consulting company found the ammunition in a cubby hole at his desk and shotgun shells in the trash basket, O'Reilly said.

In McDermott's home, authorities discovered bomb-making magazines; three gallons of nitric acid — which can be used to make nitroglycerine — in boxes labeled "Danger, do not move"; blasting caps and more ammunition, O'Reilly said.

Prosecutors said McDermott did not have a permit for any of the weapons; he also had no criminal record.

Some of the four women and three men killed worked in the accounting department, which was recently ordered by the Internal Revenue Service to seize a portion of McDermott's wages. Last week, he had an angry outburst over the dispute, said one employee, who spoke on the condition of anonymity.

However, the company said in a statement: "There was no way to anticipate his actions or any apparent reasons to restrict his access to the building."

Edgewater had recently agreed to comply but was going to wait until after the holidays, Middlesex County District Attorney Martha Coakley said. The amount owed was "a couple thousand" dollars, said a person familiar with the IRS order, who spoke on the condition of anonymity.

The company will remain closed until after New Year's Day, Coakley said.

Co-workers and neighbors described the former Navy submarine electrician as quiet, surly and quirky.

McDermott was a software tester who had worked at the company since March, said Mike Stanley, a team projects leader. He said McDermott recently had been coming in late and his performance wasn't as good as it could have been.

McDermott went by the nickname "Mucko" — something his nieces and nephews came up with when they couldn't pronounce Michael, according to a co-worker. He even had it on his car's license plate.

A person who identified himself as Michael M. McDermott and who used the e-mail name "Mucko" frequented Internet forums and gave advice on explosives.

Most of the postings contain highly technical explanations of chemical reactions, touching on everything from controlled demolition to pyrotechnics. Others give a hint at his sense of humor, with postings on a "tasteless" jokes forum.

In one exchange, someone who said he was trying to help protect Christians in Indonesia asked advice on where to buy or build land mines.

McDermott responded: "It would seem that some 'Christians' have forgotten the Sixth Commandment. It is hard to imagine Jesus resorting to land mines."

The Sixth Commandment admonishes "thou shall not kill."

Kevin Forzese, who lived upstairs from McDermott in Haverhill, said his neighbor had never mentioned money problems.

"He said he was doing real well," Forzese said. He also said McDermott had mentioned that he collected antique guns, but he had never seen any weapons in McDermott's apartment.

The victims were identified as Jennifer Bragg-Capobianco, 29, from marketing; Janice Hagerty, 46, a receptionist from Stoneham; Louis Javelle, 58, of Nashua, director of consulting in the company's Manchester, N.H., office; Rose Manfredi, from payroll, who would have been 49 on Wednesday; Paul Marceau, 36, of Melrose, a development technician; Cheryl Troy, 50, the human resources director; and Craig Wood, 29, of Haverhill, from human resources.

After Wednesday's hearing, McDermott's parents stood next to his lawyer but would not give their names.

"They are devastated," Reddington said.