ATLANTA — Federal agents spied on the widow of the Reverend Martin Luther King Jr. for several years after his assassination in 1968, according to newly released documents that show the FBI worried about her following in the footsteps of the slain civil rights icon.

In memos that show Coretta Scott King was being closely followed by the government, the FBI noted concern that she might attempt “to tie the anti-Vietnam movement to the civil rights movement.”

Four years after Martin Luther King Jr.’s death, the FBI closed its file on Coretta Scott King, saying, “No information has come to the attention of Atlanta which indicates a propensity for violence or affiliation of subversive elements,” according to a memorandum dated November 30, 1972.

The documents were obtained by Houston television station KHOU in a story published yesterday. Coretta Scott King died in January 2006 at the age of 78.

The Reverend Joseph Lowery, who served as president of the Southern Christian Leadership Conference — which King cofounded in 1957 — said the documents illustrate the FBI’s pattern of “despicable and devious” civil-rights-era behavior against the organization and those affiliated with it.

“The FBI kept a microphone everywhere they could where the SCLC was concerned,” said Rev. Lowery, who said the agency had a member of the SCLC’s staff on its payroll.

“Since we had nothing to hide, it was no great problem for us. But we don’t put it past the FBI; [then-FBI Director] J. Edgar Hoover hated Martin Luther King and everything that the SCLC stood for.”

Andrew Young, a lieutenant of King’s during the civil rights movement, agreed. But he said he was surprised that the government would focus on Coretta Scott King.

“I didn’t know it, and I don’t think she knew it,” Mr. Young said. “If ever there was a woman that had the makings of a saint, it was Coretta. I don’t know what they were looking for, I don’t know what they were expecting to find. I don’t know why they wasted the government’s money.”

Also included in the documents:

• The FBI suggested that Ralph Abernathy, a close aide to Martin Luther King, be made aware of death threats against his life for the benefit of “the disruptive effect of confusing and worrying him.”

• An intercepted letter written by Coretta Scott King in 1971 to the National Peace Action Coalition, in which she said the Vietnam War has “ravaged our domestic programs.”

• One memo shows that the FBI even read and reviewed Coretta Scott King’s 1969 book about her late husband, “My Life with Martin Luther King Jr.” The agent made a point to say that her “selfless, magnanimous, decorous attitude is belied by … [her] actual shrewd, calculating, businesslike activities.”

There is also evidence that the Nixon administration and then-Secretary of State Henry Kissinger were kept informed of the FBI’s nearly constant surveillance.

Martin Luther King Jr.’s activities were known to have been monitored by the federal government as he led the civil rights movement in the Intelligence gathering on famous Americans and war critics became so infamous that rules to curtail domestic spying were put in place in the 1970s.

King’s nephew, Isaac Newton Farris Jr., said the surveillance of his aunt comes as no surprise. “We knew she was surveilled,” said Mr. Farris.