“I never thought of Richard as a violent person before,” said Mario Galluci, a lawyer who has known Mr. Luthmann for 15 years. “Was he flamboyant? Was he a little eccentric? Absolutely. Did I always agree with his politics? Absolutely not. But what I’ve been reading doesn’t fit the profile. It almost sounds like he lost touch with reality.”

The broad allegations against Mr. Luthmann were contained in court papers charging him with running an outlandish criminal scheme from his office on Victory Boulevard, a few blocks from the Staten Island Expressway. In an indictment issued on Friday, in Federal District Court in Brooklyn, prosecutors said that Mr. Luthmann joined forces with a blind man and two reputed mobsters to pack shipping containers with “cheap filler material” and fraudulently sell them to a group of local businesses as scrap metal. In the midst of the plot, prosecutors claim, Mr. Luthmann turned on one of his partners and had him held at gunpoint to collect a $7,000 debt.

But according to the government, the scrap-metal operation was only the tip of Mr. Luthmann’s iceberg of misconduct. In a detailed memorandum that describes conduct not charged in the indictment, prosecutors said that for the past several years, Mr. Luthmann has wielded lawsuits, social media attacks and threats of physical violence to wage a series of “bullying campaigns” that furthered his “vendettas against his perceived enemies.”

Staten Island is notorious for its operatic local politics, and much of Mr. Luthmann’s anger, those who know him said, stemmed from his own failed political career. In 2013, he mounted a campaign for borough president, but was kicked off the ballot after courts determined that he lacked sufficient signatures to qualify. One month after his bid for office ended, he crashed his car into a guardrail in the middle of the night and was arrested and charged with drunken driving. While the charges made an embarrassing splash in the Staten Island media, they were eventually dismissed.

Being scorned by Staten Island’s political establishment so enraged Mr. Luthmann, prosecutors said, that he undertook an aggressive social media campaign against John Gulino, the chairman of the borough’s Democratic Party committee. According to court papers, Mr. Luthmann posted images of Mr. Gulino on the internet with hostile hash tags like “#targetpractice” and “#hunting season.” Not long after, prosecutors said, he asked one of his partners in the scrap-metal plot — a man alleged by the government to have Mafia connections — to “beat up” Mr. Gulino. The prosecutors also said that Mr. Luthmann asked the man to murder Kevin Elkins, the party committee’s former executive director.