The FBI says Den Hollander was the "primary subject in the attack" on Monday at the home of US District Judge Esther Salas in North Brunswick, New Jersey, where 20-year-old Daniel Anderl was killed and his father, Mark Anderl, 63, was wounded.
Salas, 51, was in another part of the house and was unharmed. Den Hollander was found dead later in Sullivan County, New York.
In both attacks, the suspect appeared to pose as a delivery driver, according to a law enforcement official.
Investigators found items in Den Hollander's possession that prompted concerns about whether he had targeted, or planned to target, other people. The items included a photograph of New York Chief Judge Janet DiFiore and the address of a state appeals courthouse, a state court spokesperson said.
Den Hollander, 72, described himself as an "anti-feminist" lawyer who filed lawsuits challenging the constitutionality of "ladies night" promotions at bars and nightclubs, sued Columbia University for providing women's studies classes, and sued news organisations over what he said was biased coverage.
In more than 2,000 pages of often misogynistic, racist writings posted online, Den Hollander had sharply criticized Salas and other female judges.
Both Den Hollander and Angelucci, 52, were involved in lawsuits seeking to force the US government to require all young women to join men in registering for a possible military draft.
- AP
