The Rev. Samuel Billy Kyles, a longtime civil rights leader who was present when Martin Luther King Jr. was assassinated on a hotel balcony, has died in Memphis. He was 81.

Erica Cunningham, an administrative assistant at Monumental Baptist Church in Memphis, where Kyles served as pastor for 55 years, said he died Tuesday at a hospital. An official cause of death was not immediately released, but Cunningham said he had been living with dementia. Kyles' family is expected to release a statement later.

King came to Memphis in 1968 to help striking sanitation workers, who were seeking safer working conditions and better pay. At about 6 p.m. on April 4, King, Kyles and others prepared to leave the Lorraine Motel to go to dinner.

"I said, guys, come on let's go. We have a rally after dinner," Kyles told The Associated Press in a 2008 interview. "I turned and walked away, got a few steps, a few feet, and that's when I heard the shot."

The .30-caliber bullet hit King, who was on a balcony with Kyles and others.

"Blood was everywhere," Kyles recalled.

Kyles was the subject of a 2008 documentary short film about the assassination, "The Witness: From the Balcony of Room 306." The film was nominated for an Academy Award.

Kyles was born in Shelby, Mississippi, on Sept. 26, 1934. He came to Memphis and became pastor of the Monumental Baptist Church beginning in 1959. He resigned in October 2014 because of his declining health.

He worked on behalf of voter registration drives in Mississippi and was in that state when activist Medgar Evans was assassinated for his civil rights work in 1963.

He was credited with helping integrate schools in Memphis when, working with other parents, he enrolled his 5-year-old daughter in the all-white school system.

Memphis became one of the first cities in the South to desegregate its elementary schools. Kyles also fought against segregation on the city bus system and to gain admittance for blacks in Memphis restaurants and movie theaters.

Kyles also helped found the Memphis chapter of People United to Save Humanity (PUSH).

In 1996, then-President Bill Clinton appointed Kyles to the Advisory Committee on Religious Freedom Abroad. Kyles also is among the civil rights figures honored at the International Civil Rights Walk of Fame at the National Civil Rights Museum, which is on the site of the Lorraine Motel.

"Rev. Kyles remained on the frontline for justice and equality, a tremendous civil rights activist," the museum said in a statement. "He was a man of great courage, compassion and faith."

In a statement, U.S. Rep. Steve Cohen, a Democrat from Memphis, called Kyles "a legendary clergyman and civil rights advocate."