Roy Den Hollander, the men’s rights activist who reportedly opened fire on a New Jersey federal judge’s husband and son, had terminal cancer and a long history of failed anti-feminist lawsuits.

Den Hollander is suspected of posing as a FedEx deliveryman before fatally shooting the 20-year-old son of Judge Esther Salas and wounding her defense attorney husband at their North Brunswick home. He fatally shot himself near Liberty, New York, after the ambush, according to reports.

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In a frightening twist, the FBI on Monday contacted New York state’s chief judge, Janet DiFiore, to notify her that Den Hollander had her name and photo in his car, her spokesman, Lucian Chalfen, confirmed.

About a dozen FBI agents were searching for clues at Den Hollander’s Stuyvesant Town apartment Monday night.

According to court documents, Den Hollander had been a lawyer in a case pending before Salas challenging the military’s male-only draft. The self-described “anti-feminist” had railed against the gender-based service requirement, which he described as an attack on men’s rights.

Den Hollander was taken off the case in June 2019. The plaintiff hired a new attorney.

Den Hollander had attached himself to other so-called male oppression crusades. A Manhattan Supreme Court judge said Den Hollander was not the victim of age and gender discrimination in 2010 when a bouncer at Amnesia nightclub told him to pay up, while letting a young lady in for free.

"There's no justice for guys in this day and age," Den Hollander said at the time.

He also sued several Manhattan hot spots, including the Copacabana, for organizing “ladies’ nights” drink specials. The suit was thrown out by a federal appeals court in 2010.

In 2008, Den Hollander also sued Columbia University, claiming it discriminates against men by teaching a doctrine that scapegoats men for all of history’s troubles.

Den Hollander was suffering from terminal cancer, as he revealed in a lawsuit he filed in February against NewYork-Presbyterian Hospital. In a post on his website, he referred to Salas as a “lazy and incompetent Latina judge appointed by (Barack) Obama.”

He flaunted his misogyny in interviews.

“If I’m hitting on some young girl at the club -- and I won’t be hitting on an older one because they don’t look as good -- if she knows how old I am I’m not going to be able to exploit her infinite capacity to delude herself into thinking I’m younger,” he told the New York Daily News in 2013, explaining why he wouldn’t share his age.

Beneath the absurdity of his losing legal battles and attempts to get into nightclubs was bitterness and hatred of women.

“I’m beginning to think it’s time for vigilante justice -- civil disobedience,” he said in 2013, adding he “may pull a Carrie Nation on the ladies’ nights clubs.”

Nation, who died in 1911, was a radical member of the temperance movement who vandalized bars with a hatchet.

Den Hollander’s website rails against “Feminazism” and features a bizarre, conspiratorial screed against a Russian woman he married in 2000. He wrote that he met her while managing a Moscow detective agency, Kroll Associates. Den Hollander claimed in a lawsuit seething with anti-immigrant sentiment that the woman began working at the strip club FlashDancers and used him only in an effort to obtain citizenship.

When Den Hollander announced his lawsuit against the New York hospital for treatment of his metastasized cancer, the news release was titled “How not to treat a dying man.”

He had nothing to lose.

“They want to fight, fine. I’ll fight them to my last dollar, my last breath and if there is anything after death -- for eternity. They should have shown a little more respect for a dying man,” he wrote in the release.