(CNN) -- A previously unheard recording of Martin Luther King Jr. discussing John F. Kennedy will be played Monday in the place where the civil rights leader was assassinated.
King's comments are on a 53-year-old reel-to-reel tape discovered in a Tennessee attic several years ago. But the last several minutes are only now being made public.
The civil rights leader is heard discussing Kennedy's role in securing his release from a Georgia prison after he was sentenced to four months of hard labor for a traffic violation two weeks before the election that sent Kennedy to the White House.
Then-Sen. Kennedy placed a call to Coretta Scott King against the advice of close advisers, expressing his concern to King's wife. His brother, Robert Kennedy also called the Georgia judge who had sentenced King to the chain gang and denied him bond. King was freed the next day.
The interviewer asked Dr. King if he thought Kennedy had any influence on his release.
"Well, I would say first that many forces worked together to bring about my release," King said. "I don't think any one force brought it about, but you had a plurality of forces working together. I'm sure that the interest of the public, in general, all over America had something, a great deal to do with it."
In fact, Atlanta Mayor William Hartsfield was working to negotiate King's release from incarceration, which began with his arrest during a protest eight days earlier, according to Taylor Branch's historical account in his book, "Parting the Waters."
"Now, it is true that Sen. Kennedy did take a specific step," King said. "He was in contact with officials in Georgia during my arrest and he called my wife, made a personal call and expressed his concern and said to her that he was working and trying to do something to make my release possible."
John F. Kennedy made the call to King's wife at the urging of his brother-in-law Sargent Shriver, but out of the presence of campaigns aides who were concerned it could cost him southern support in the election 13 days away, Branch wrote.
Robert Kennedy, who was initially upset when he found out about the call, reversed himself later that day and placed his own call to the judge, Branch wrote. King told the interviewer he thought it had "some part" in his release.
"His brother, who at that time was his campaign manager, also made direct contact with officials and even a judge in Georgia, so the Kennedy family did have some part, at least they expressed a concern and they did have some part in the release, but I must make it clear that many other forces worked to bring it about also."
The Kennedys' intervention is credited with shifting support of Black voters in crucial northern states to the Kennedy side and away from Richard Nixon, whose campaign only offered a "no comment" when asked about the civil rights leader's imprisonment.
The recording is from an interview conducted on December 21, 1960, in Chattanooga, Tennessee, by a man who intended to write a book about the civil rights movement. He never finished the book and the tape was lost until the man's son rediscovered it five decades later while rummaging through dilapidated boxes left there by his father.
The first five minutes, in which King discusses his definition of nonviolence and its importance in the civil rights movement, was made public in 2012.
"I would ... say that it is a method which seeks to secure a moral end through moral means," he said. "And it grows out of the whole concept of love, because if one is truly nonviolent that person has a loving spirit, he refuses to inflict injury upon the opponent because he loves the opponent."
King continued, "I am convinced that when the history books are written in future years, historians will have to record this movement as one of the greatest epics of our heritage," he said. "It represents struggle on the highest level of dignity and discipline."
In another part of the recording, King describes his visit to Nigeria and the importance of the civil rights movement in the United States and abroad.
"There is quite a bit of interest and concern in Africa for the situation in the United States. African leaders in general, and African people in particular are greatly concerned about the struggle here and familiar with what has taken place," he said, "We must solve this problem of racial injustice if we expect to maintain our leadership in the world, and if we expect to maintain a moral voice in a world that is two-thirds color."
Keya Morgan, a collector and expert on rare historical artifacts, brokered its sale to illusionist David Copperfield, who then donated the tape to the National Civil Rights Museum, which is housed in the Lorraine Motel in Memphis.
King was shot to death standing on a balcony of the Memphis, Tennessee, motel on April 4, 1968. The entire recording will be played Monday in the last room where the civil rights leader slept.
"When I heard it, I got goose bumps all over," Morgan said, "It feels like he's sitting in your living room and talking to you."
"It gave me chills," Copperfield told CNN in September 2012, when he bought the tape for an undisclosed amount. It was striking because the recording revealed King in a relaxed mood, he said.
"We've heard Dr. King talk about peaceful change in the public forum, but this is an audio tape of him talking conversationally," he said. "I'm certainly no expert, but it's the first time I've ever heard him in that context and I was very moved by it."
Copperfield said he gave the recording to the museum because it "is just the right thing to do."
"He's certainly one of the great inspirational figures in history," Copperfield said. "So much of what I do, in my own little way, is making people dream, transporting them, making them think differently. That's what magic does. His dream was far greater than any entertainer can provide."