Investigators said they have seized 83 guns and 10,000 rounds of ammunition from the Lexington home of a man charged with putting banana peels on the property of a family of color in his neighborhood.

Robert Ivarson, 49, will face 13 new charges in connection with the discovery of the arsenal, said Middlesex District Attorney Marian Ryan.

“It is our belief at this point that that residence on Tarbell Avenue is secured, and that neighborhood is certainly a much safer place,’’ Ryan said at a news conference Friday afternoon.

Items seized also included a World War II German-style helmet with a Nazi insignia and 50 pounds of black powder.

Ivarson’s parents, who live in the same home, are cooperating with law enforcement, and investigators do not believe they had a role in their son’s possession of the weapons, Ryan said.

She said there were areas of the home that only Robert Ivarson could access.

Ivarson’s parents declined to comment when they arrived home shortly before 5 p.m. on Friday.

Their two-story, blue-shingled home had an American flag hanging by the front door, as well as elaborate carvings of smiling faces, a bird, and a cherub. Police executed a search warrant on the property Thursday night.

Ivarson was charged with three counts each of possession of a firearm without a license, possession of ammunition without a license, possession of a large-capacity firearm, and possession of a large-capacity feeding device.

Ivarson also was charged with being an armed career criminal, meaning he has at least two prior violent offenses on his record, Ryan said.

She said the massive seizure of the guns and black powder “provides safety that did not exist yesterday in that neighborhood.’’

Ryan said she was troubled by the initial charges that Ivarson had violated his neighbors’ civil rights with his alleged vandalism.

“People have a right to be safe and secure in their home and in their neighborhood,’’ she said, adding that racially motivated acts “cannot be tolerated.’’

Lexington Police Chief Mark Corr also denounced Ivarson’s alleged actions.

The town “feels very strongly about celebrating diversity,’’ Corr said in a statement issued after the news conference. “We do not condone behaviors that violate people’s civil rights.’’

Corr also commended his officers for “their hard work and commitment to this case.’’

Ivarson was under surveillance by Lexington police when he allegedly threw the peels onto his neighbor’s driveway on Tarbell Avenue on three consecutive mornings last week, according to a Lexington police report. The family had reported seeing 30 to 40 peels outside their home over the past year, police said.

Ivarson denied any malicious intent when he spoke with officers at the Lexington police station, claiming that he takes daily walks for exercise and tosses banana peels at random along his route, according to the report.

He was arraigned Tuesday in Concord District Court on civil rights and harassment charges. Not-guilty pleas were entered on his behalf and bail was set at $10,000 cash. He is being held in lieu of the cash bail, officials said.

Authorities were working to determine how Ivarson obtained such a large amount of weapons, Ryan said.

It was not clear what, if anything, Ivarson intended to do with the items that police seized, she added.

“Obviously, the possession of any illegal firearm on the street poses a safety risk,’’ Ryan said, standing just feet from where the weapons were displayed on a table.

“When you look about this room today, and you look at the amount of material that was taken from that home, it’s very easy to understand the threat that was posed, both in that home and to that neighborhood,’’ Ryan said.

Ivarson will be arraigned in Concord District Court Monday.

Ivarson already faced civil rights and harassment charges for repeatedly putting banana peels on the property of a family of color.

There was no answer at the family’s home Friday night.

Neighbors on the well-kept street expressed shock at the large number of weapons retrieved from the Ivarson residence.

“Eighty-three?’’ a male neighbor asked, referring to the number of guns. “That’s your number?’’

The man, who would not give his name, said he has been neighbors with the Ivarsons for 40 years and never had any problems with Robert Ivarson.

“He’s a guy,’’ the man said. “That’s all I can say.’’

A female neighbor, who would also not give her name, said she was disturbed by the revelation about the guns.

“It’s pretty scary,’’ she said.

A third neighbor put her hands to her face when told of the guns, ammunition, and Nazi helmet that police seized.

“It’s a horrible situation,’’ she said, adding that she had never spoken with Ivarson.

Mike Bello and John Ellement of the Globe staff contributed to this report. Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.