In the days and months leading up to a fatal July 4 shootout in Yellowstone National Park, federal prosecutors say Samson “Lucas” B. Fussner sent signals that he was planning “pro white nationalist violence.”

Back in March, the 28-year-old Florida man logged onto a forum known for its white supremacist and antisemitic worldviews, posting that he was “on the precipice of a breakdown” and suggested he might make “a last stand.”

Fussner wrote that he planned to find a seasonal job in a “nice white mountainous area or state park,” but, he said in the March 16 post, “if I am still unable to make something of that experience, look forward to someday seeing me in the news.”

Fussner would be shot dead by Yellowstone rangers less than four months later. He was killed after holding a female coworker hostage and shooting a ranger — and just before he attempted to carry out a mass shooting at an employee dining hall and potentially elsewhere, federal authorities say. The ranger survived the shot to his foot, but lost multiple toes due to the injury, according to prosecutors.

Fussner’s shooting spree has been well-publicized, but the U.S. Attorney’s Office for the District of Wyoming released new details about the events leading up to the crime in a Friday court filing. Assistant U.S. Attorney Jeremy Gross and FBI Special Agent Eric Barker laid out the allegations in a verified complaint that seeks to have Fussner’s SUV, four guns and various magazines and ammunition forfeited to the government. Gross contends that all of the items were connected to a plot to carry out an act of terrorism.

“In attempting to carry out an attack on the employee dining room at Canyon Lodge, and in actually shooting at federal [National Park Service] employees, Fussner intended to influence or affect the conduct of government by intimidation or coercion, or to retaliate against government conduct,” Gross wrote.

In the filing, the prosecutor says Fussner “had a history of expressing white supremacist and antisemitic views,” including on the Vanguard News Network forum. Not long after his March post to that forum, Fussner landed a summer position with a Yellowstone concessionaire. However, according to text messages obtained by federal prosecutors, Fussner became upset and despondent about the large number of non-white workers in the park, his problems with women and his mental health.

He vented to a brother in a series of early July messages in which he used racial slurs for Chinese and Hispanic people, expressed anger toward Jewish people and talked about the possibility of shooting people during a fireworks show.

“... crowds there will be easy targets,” Fussner reportedly wrote.

On July 3, Fussner sent another text about his life being meaningless and wanting a death that was “fun and had some kind of meaning.” The filing doesn’t say how Fussner’s brother responded to the texts.

Fussner had reportedly become “obsessed” with a female coworker, the filing says, and after she rebuffed his romantic advances, he forced his way into her dorm room around 10 p.m. on July 3. He at one point pulled out a knife, then pulled out a handgun and told the woman he was taking her hostage.

Over the course of the next two hours, Fussner “ranted about his mental health issues,” “made inflammatory comments about immigrants, African Americans and Jews” — including calling all black people evil — and shared plans to carry out mass shootings at the employee dining room at Canyon Lodge and at a fireworks show in West Yellowstone, the filing says. He also specifically discussed plans to shoot Jewish children.

“Fussner indicated that he wanted people to go down with him, so he had to do something major,” Gross recounted in the document. “He wanted to make a statement because politics in America are messed up and law enforcement was going to have to kill him.”

Fussner left the woman’s room around midnight, after her roommate arrived home. The woman then contacted the concessionaire’s security staff, which contacted the Park Service.

Rangers searched for Fussner through the night, but only found his empty 2021 Nissan Rogue. Inside was a .38 caliber pistol and a magazine, with a 12 gauge shotgun later found stashed inside a guitar case.

Fussner had backed the Nissan into a parking spot just outside the lodge, which law enforcement now believes was a tactical decision, “so that he could make a speedy getaway to the next location.”

Rangers were posted around Canyon Lodge, and just after 8 a.m. on July 4, one of the officers saw Fussner come out of the trees and start walking toward the lodge with an AR-15-style rifle. Fussner opened fire — shooting one of the rangers near the lodge’s loading dock before being shot and killed by the officers.

“Somehow, due to the quick response and positioning of law enforcement, Fussner was not able to harm anyone further,” Gross wrote.

In addition to the Anderson Manufacturing AR-15 rifle, Fussner also had a 9mm Glock 17 pistol and “numerous” magazines with ammunition, the filing says. The U.S. Attorney’s Office is now asking a judge to forfeit those weapons to the federal government, along with the two weapons found in the Rogue and the vehicle itself. If there are no objections and U.S. District Judge Scott Klosterman agrees, the items and any potential proceeds from their sales will go to the government.