The former vice president of the Oglala Sioux Tribe and a longtime Native rights activist died Sunday from complications due to the coronavirus.

Tom Poor Bear, 66, died at the North Colorado Medical Center in Greeley, Colorado.

“I still can’t believe Tom has left us,” said Bryan Brewer, who served as president of the Oglala Sioux Tribe with Poor Bear as his vice president. “It’s a bad day for the tribe and his family.”

Poor Bear joined the American Indian Movement not long after they came to the Pine Ridge Reservation in South Dakota in 1972. He ran away from boarding school to jump in a car and ride to Washington, D.C., where AIM took over a Bureau of Indian Affairs building to protest the federal agency’s failure to fulfill its trust responsibilities to Native people.

Poor Bear continued to seek justice for Native people, and in 1999 he began fighting beer sales in Whiteclay, Nebraska, an unincorporated village on the reservation’s southern border that once sold as much as 4 million cans of beer a year mostly to residents of the dry Pine Ridge Reservation.

His fight against Whiteclay beer sales was a deeply personal one, driven by the murder of his brother, Wilson Black Elk Jr., and cousin, Ron Hard Heart, whose bodies were found in a field between Whiteclay and Pine Ridge on June 8, 1999.

Along with other activists such as the late Russell Means and the late Frank LaMere, Poor Bear fought to close the beer stores and to seek justice for his brother and cousin, hosting annual marches to Whiteclay for many years.

“I made a commitment I wouldn’t walk away from their spirits,” he told a reporter for the Rapid City Journal in 2009. “We’re going to keep marching until justice is found.”

Poor Bear left office in November after he decided to not seek re-election as vice president, an office he gained after he was chosen to finish the term of former tribal vice president Darla Black, who was impeached last year.

Kevin Killer, the Oglala Sioux Tribe’s newly inaugurated president, said Poor Bear inspired him and many other young leaders with his courageous efforts to bring attention to Native causes. He cited Poor Bear’s success at gaining former President Barack Obama’s attention during a presidential speech in Denver in October 2011, when Poor Bear unfurled a banner that read “President Obama, Yes You Can Stop the Keystone XL Pipeline” and called out to the president.

Obama paused from his prepared remarks and acknowledged Poor Bear, saying “I hear you. No decision has been made. I know your deep concern about it. We will address it.”

Four years later, the president fulfilled his promise when he rejected the controversial pipeline, a decision later reversed by President Donald Trump in one of his first official acts.

“He never stopped fighting,” said Jane Kleeb, founder of Bold Nebraska, a coalition formed to stop the Keystone XL pipeline.

Killer said Poor Bear supported his own efforts to fight for Lakota people as a state senator in South Dakota.

“It’s a hard loss for our community because of everything that he stood, what he stood for and how he did it,” he said. “I’m glad that he’s not suffering anymore.”

The Oglala Sioux Tribal Council hosted an honoring song for Poor Bear on Monday.

Brewer also lamented the November 10 death of Debra White Plume, a longtime treaty rights activist who had protested the Keystone XL pipeline and the Dakota Access Pipeline. Standing alongside Poor Bear during a Keystone XL protest in New York City in November 2011, the two activists were arrested at the same time.

Brewer said he learned the two had marched together just a few hours before learning they had been arrested together.

“The next thing I knew they were both in jail,” he said.

During an interview posted on YouTube last year, Poor Bear talked about the empowering effects of AIM activists coming to his reservation in 1972. After years spent learning a version of American history in the boarding school he attended that belittled indigenous peoples’ contributions, Poor Bear finally learned of the resilience of the Lakota people from the activists who came to Pine Ridge that year.

“They never told us of our great leaders of the past, of Sitting Bull, of Gall, of Crazy Horse, of Red Shirt, of Spotted Tail, of Geronimo,” he said of his boarding school teachers. “But the American Indian Movement told us how great we were, how great our people were, how respectable our people were.”

“They brought the pride out in indigenous people.”