U.S. President Donald Trump on Tuesday pardoned Oregon cattle ranchers Dwight Hammond and his son after both were convicted on arson charges, sparking the 2016 occupation of a wildlife refuge, according to a White House statement.

The Hammonds’ case led to the armed 41-day occupation of the Malheur National Wildlife Refuge, during which one occupier was shot dead by police. The takeover was the latest flare-up in a decades-old conflict over federal control of millions of acres of public land in the Western United States.

Dwight Hammond, 76, and his son, Steven, 49, were convicted in 2012 for setting a fire that spread onto public grazing land.

The two were initially sentenced to less than the legal minimum five-year prison sentence for their crimes, but a federal judge in 2016 ordered the pair returned to serve the full five years, after the father had spent three months in prison and the son one year, according to 2012 court documents.

The order to return to prison inspired the refuge occupation. The White House in a statement on Tuesday called the order to return the two to prison “unjust.” As of 2018, Dwight had served approximately three years in prison and Steven had served four, according to the White House.

The leaders of the 2016 Malheur standoff, including activist Ammon Bundy, in October 2016 were cleared of federal charges for their role in the protest. One of the occupiers, Robert “LaVoy” Finicum, was shot dead by Oregon State Police during the takeover.

Ammon Bundy and his father, Cliven, also orchestrated a 2014 standoff in Nevada between scores of armed ranchers and supporters and law enforcement agents over cattle grazing rights.

Malheur National Wildlife Refuge, encompassing 292 sq. miles (75,628 hectares), was established in 1908 by President Theodore Roosevelt as a breeding ground for greater sandhill cranes and other native birds.