A 69-year-old man armed with a rifle threw incendiary devices at an immigration jail in Washington state early on Saturday morning, then was found dead after four police officers arrived and opened fire, authorities said.

A friend of the dead man said she thought he wanted to provoke a fatal conflict, the Seattle Times reported, and described him as an anarchist and anti-fascist.

The Tacoma police department said the officers responded about 4am to the privately run Tacoma Northwest Detention Centre, a Department of Homeland Security detention facility that holds migrants pending deportation proceedings.

The detention centre has also held immigration-seeking parents separated from their children under Donald Trump’s “zero tolerance” policy, an effort meant to deter illegal immigration.

The shooting took place about six hours after a peaceful rally in front of the detention centre, police spokesman Loretta Cool said.

The Pierce county medical examiner’s office identified the man as Willem Van Spronsen of Vashon Island, the Tacoma News-Tribune and the Seattle Times reported.

Police said Van Spronsen caused a vehicle to catch fire and attempted to ignite a large propane tank and set buildings alight. Police said that besides the rifle, he had a satchel and flares.

Police said officers called out to Van Spronsen and shots were fired.

Officers then located Van Spronsen and determined he had been shot and was dead. Authorities said investigators were processing the scene and police are continuing to investigate. No law enforcement officers were injured.

A motive for Van Spronsen’s actions had not been determined, Cool said.

A friend of Van Spronsen, Deb Bartley, told the Seattle Times she had been a friend for about 20 years. She described Van Spronsen as an anarchist and anti-fascist and said she believed his attack on the detention center was meant to provoke a fatal conflict.

“He was ready to end it,” Bartley said. “I think this was a suicide. But then he was able to kind of do it in a way that spoke to his political beliefs. I know he went down there knowing he was going to die.”

She said she and other friends of Van Spronsen got letters in the mail “just saying goodbye”. He also wrote what she referred to as a manifesto, which she declined to discuss in detail.

Van Spronsen was accused of assaulting a police officer during a protest outside the detention centre, the News-Tribune reported. According to court documents he lunged at the officer who was trying to detain a 17-year-old protester on 26 June 2018.

Van Spronsen pleaded guilty to the charge of obstructing police and was given a deferred sentence in October, the News-Tribune reported.

GEO Group, which runs the 1,575-bed Northwest Detention Centre, in an email to the Associated Press said baseless accusations about how detainees were treated at its facilities “have led to misplaced aggression and a dangerous environment for our employees, whose safety is our top priority.

“Violence of any kind against our employees and property will not be tolerated. We are thankful for the quick and brave action by the Tacoma police department, which prevented innocent lives from being endangered.”

In 2018 a federal judge ruled that Washington state could pursue its lawsuit seeking to force GEO Group to pay minimum wage for work done by detainees at the detention centre.

In November a Russian asylum-seeker who conducted a hunger strike in protest at conditions in the detention centre died by suicide, the county medical examiner’s Office ruled.

Mergensana Amar, 40, was taken off life support after attempting to kill himself while in voluntary protective custody at the detention centre on 15 November, US Immigration and Customs Enforcement said.