In the pre-dawn hours of February 28, 1992, a makeshift bomb detonated in the first floor office of a prominent animal science professor at Michigan State University. The explosion and the resulting blaze injured no one, but spread into three nearby workspaces before firefighters put it out.

When the smoke cleared, more than three decades of research, some of it unpublished, had been reduced to ash. In addition to the lost data, the fire caused more than $1 million in property damage. (The attack and the criminal case that followed were covered extensively by the Lansing State Journal.)

The Animal Liberation Front, an extremist animal rights collective, immediately claimed responsibility. In a news release, the group said it had targeted the office because researchers had conducted cruel experiments on minks.

Investigators said all signs pointed to the group’s spokesman, Rodney Coronado, as the main suspect. The 26-year-old activist was in Michigan at the time of the bombing and was believed to have participated in similar acts of sabotage in other states. He had gone into hiding shortly after the attack.

It took 14 months, but authorities eventually found Coronado living on a Native American reservation in Arizona and arrested him. Facing 50 years in prison, he pleaded guilty to aiding and abetting arson in exchange for having other charges dropped. In 1995, he was sentenced to four years and nine months in prison.

Despite his plea, Coronado long insisted he wasn’t behind the bombing. He took the deal because he didn’t think he could win the case, he said at the time. He conceded that he was in Michigan during the attack, but only in his capacity as Animal Liberation Front’s spokesman.

But in an interview published Thursday with the Lansing State Journal, Coronado came clean: he alone was responsible for the attack.

“There are no looming criminal charges against me,” he said of his decision to admit involvement. “I’m as free as any person in this country can be.”

For Coronado, now 50, the confession seems to be part of a broader change of heart he has experienced as he has grown older. He said years in prison and becoming a father cause him to reexamine his beliefs. Though he is still dedicated to animal rights activism, he no longer advocates using violence and intimidation to accomplish his goals.

“Changing attitudes is done with communication,” he told the State Journal. “Our efforts are damaged when you push someone against a wall and antagonize with direct action.”

Coronado was already something of a veteran among animal rights activists when he carried out the attack at Michigan State. His activism dates back to his teenage years, when he joined the Sea Shepherd Conservation Society, a collective that uses direct action to protect marine life. While there, he and an accomplice destroyed a whaling plant in Iceland and opened the seacocks of two whaling vessels, causing them to sink up to their masts, according to a 1995 Rolling Stone profile.

Later, he penetrated fur farming operations in the United States and on more than one occasion broke into facilities to free captive animals, including lynx and bobcats. He was also linked to an Animal Liberation Front firebombing of a fur farm in at Oregon State University and other attacks.

The 1992 attack at Michigan State targeted one researcher in particular, Richard Aulerich, who had studied mink reproductive habits at a mink ranch built on the college’s campus since the 1940s.

Coronado believed Aulerich was being supported by the commercial fur industry and needed to be stopped. At 5 a.m. on the day of the attack, he broke open Aulerich’s door and set the timer on the bomb. On the way out, he scrawled “fur is murder” and “Aulerich tortures minks” on the walls in red paint.

“I won’t sugar coat it; we were about psychological warfare,” Coronado told the State Journal. “We wanted researchers like Aulerich never to know when they came to work and opened their office door whether there had been an attack. We wanted them to live in fear.”

The blaze burned 32 years of Aulerich’s research, which did assist the fur farming industry, but focused more on environmental impacts on minks, according to a 1992 report in The Scientist. In an ironic twist, the fire also destroyed roughly 10 years of data gathered by another scientist who was collecting animal sperm to use as a substitute for live animal testing.

“It’ll be like starting over,” Aulerich told The Scientist at the time. “We had one of the best mink libraries in the world, and it’s gone. They even destroyed all of the animals’ identification.”

Coronado spent more than a year on the run before authorities arrested him in 1994 and charged him in connection with half a dozen Animal Liberation Front attacks. He pleaded guilty to the Michigan State bombing in exchange for having the other charges dropped.

“There is a price to be paid for this kind of terrorist activity,” the judge reportedly said at his 1995 sentencing.

In his interview with Rolling Stone that year, Coronado told the magazine that he merely acted as the Animal Liberation Front’s spokesman and denied direct involvement in the bombing.

“I’m happy with this decision because I still strongly feel I did the right thing by being in Michigan and helping to spread information and support that raid,” he said. “I know what I did. If that is a crime, and if you’re going to punish me for it, then do it. I’d rather do the time than have to denounce someone whose actions I support or have to disassociate myself from the role I had. This way I’m able to deal with the truth. That has always been my way.”

After spending more than four years in prison, Coronado returned to the activist world something of a celebrity, giving lectures around the country. Although he stopped participating in direct action, authorities monitored him closely. His legal troubles continued.

In 2003, he gave a talk in San Diego in which he described fire as a “cleansing force” and demonstrated how to rig up an explosive device using gasoline. The lecture took place a day after a fire burned down an apartment complex in the city, as the New York Times reported. The Earth Liberation Front, a group closely associated with the Animal Liberation Front, claimed responsibility. Coronado was prosecuted and sentenced to a year in prison under a terrorism statute that prohibits demonstrations of explosive devices intended for use in crimes. Shortly after he was released, he was sent back for violating the terms of his probation by accepting a Facebook friend request from a fellow activist.

Prison changed Coronado. Since 1995, he has served more than six years, an experience he described as “my greatest fear, beyond even death.” Becoming a parent changed him, too. In 2006, while in prison, he wrote an open letter to supporters renouncing violence and as a tactic for social change, saying that raising a child “requires a parent to practice the very principles you seek to teach your children.”

Since 2013, Coronado has focused on wolf conservation in the lower 48 states. He founded Wolf Patrol, a nonprofit whose mission is to change the way states treat gray wolves and encourage citizens to report illegal wolf hunting.

In a December 2016 interview with the left-wing website AlterNet, Coronado said the group — which he describes as “a tactic, not an organization” — reflected a somewhat grudging decision to walk away from the actions that landed him in prison.

“My choice is to do as I desire and spend the rest of my life in prison, or find a way to fight that allows me to stay free. It’s a purely cost-benefit analysis,” he said. “I am worth more to the wolves free than in prison. So prison has taught me that we have to evolve and learn how to fight in new ways.”

But some of Coronado’s old tendencies can still be heard in the interview with AlterNet. He told the publication that he believed activists had an obligation to “act against wanton violence and destruction, whether it be legal or not.” Factors such as jobs, children or schooling were “all excuses” for inaction, he said.

“Because you know, deep in your heart, what you should be doing,” Coronado said. “Action, not words, is what the world needs most right now.”