Charles Ogletree, the civil rights attorney and Harvard Law School professor who mentored the Obamas and represented clients including Anita Hill, Tupac Shakur and the victims of the 1921 Tulsa race riots, died on Friday, according to Harvard Law School.

He was 70. The cause of death was Alzheimer's disease, the school said.

Ogletree, born in 1952, graduated from Harvard Law School in 1978 and worked as an attorney for the District of Columbia Public Defender Service before returning to Harvard Law as a lecturer in 1984, Harvard said. Known as "Tree," he founded the Charles Hamilton Houston Institute for Race and Justice and the Criminal Justice Institute at the law school, Dean John F. Manning said in a statement.

"Charles was a tireless advocate for civil rights, equality, human dignity, and social justice. He changed the world in so many ways, and he will be sorely missed in a world that very much needs him," Manning said.

Ogletree represented several high-profile clients, including Hill when she accused Clarence Thomas of sexual harassment during Thomas' confirmation hearings for the Supreme Court, according to Harvard. He represented the rapper Tupac in his legal issues, and he defended his colleague Henry Louis Gates Jr. after his controversial arrest at his home in Cambridge, Massachusetts, in 2009.

In addition, Ogletree became one of the foremost legal advocates for reparations when he created the Reparations Coordinating Committee, a team of lawyers, academics and officials that sued on behalf of the victims of slavery and racism. Along with Johnnie Cochran and other attorneys, he represented the survivors and victims' descendants of the 1921 Tulsa race riots in a lawsuit in the early 2000s asking for reparations.

Though the suit was ultimately dismissed, it helped bring renewed attention to the riots and the broader issue of reparations.

"Very few of us have a clear sense of the actual tragic circumstances that led to the death and destruction of millions of Africans simply being transported from Africa to the United States," Ogletree said in a 2001 interview with the Harvard Law Bulletin. "It is in some sense every bit as tragic as the Holocaust, and yet it has received considerably less attention."

He added: "(T)here hasn't been a decade when the chain of discrimination and bigotry and prejudice has been unbroken. And as much as you can talk about Jim Crow laws and de jure and de facto desegregation in the 19th century, you can talk about things like racial profiling, a discriminatory death penalty, and disparity in sentencing in the 21st century."

Barack and Michelle Obama commemorated Ogletree in a statement Saturday, calling him "unfailingly helpful, and driven by a genuine concern for others."

Ogletree also created the Saturday School program at Harvard Law, a program that Barack Obama described as "for Black students who didn't necessarily have the support systems at home" to get them through law school. It eventually became so popular that students of all backgrounds began showing up to hear Ogletree, Obama said.

Ogletree retired from Harvard Law School in 2020 after he was diagnosed with Alzheimer's disease, according to Harvard. He died at his home in Odenton, Maryland, on August 4 from the disease, Harvard said.

The Obamas said Ogletree aimed to spread awareness following his diagnosis, particularly among people of color, and "wanted to be a spokesperson for the disease."

Manning, the dean, said Ogletree showed "bravery and openness" about "the illness with which he struggled in his final years."

"He had a way of teaching not just his students, but his friends, that was powerful, decent, and giving -- that without judgment helped you edge always a little closer to the best version of yourself," Manning said.

"We are profoundly grateful not just for the many contributions Charles made to Harvard Law School, but also for the tremendous legacy he created on questions of race, justice, and equality."