By DAVID KLEPPER

WASHINGTON (AP) — The CIA released nearly 1,500 pages of previously classified documents relating to New York Sen. Robert F. Kennedy and his 1968 assassination on Thursday, detailing the spy agency’s work to investigate his killing as well as previously unknown contacts between him and the agency.

Kennedy met with the CIA following a 1955 tour of the Soviet Union, relaying his observations to the spy agency as a voluntary informant, the documents show.

The newly available material comprises 54 documents, including memos about the agency’s work to investigate whether RFK’s killer had any foreign ties, as well as the response to his killing by foreign powers.

President Donald Trump had ordered the release of documents relating to the assassinations of RFK, President John F. Kennedy and Martin Luther King Jr. More than 10,000 pages of records pertaining to RFK’s assassination were released in April. The records released Thursday also included documents about the JFK and King killings, some produced after RFK’s death and dealing with conspiracy theories.

“Today’s release delivers on President Trump’s commitment to maximum transparency, enabling the CIA to shine light on information that serves the public interest,” CIA Director John Ratcliffe said in a statement. “I am proud to share our work on this incredibly important topic with the American people.”

Kennedy, a Democrat, was fatally shot on June 5, 1968, at the Ambassador Hotel in Los Angeles moments after giving a speech celebrating his victory in California’s presidential primary. His assassin, Sirhan Sirhan, was convicted of first-degree murder and is serving life in prison. One document released Thursday, a CIA memo to the White House the day after the assassination, showed that its first search of its records turned up no information about Sirhan.

Kennedy’s contacts with the CIA following his visit to the Soviet Union reflected the tensions of the time, and the high value put on personal observations of Americans who traveled to Russia and other former Soviet regions. Prominent elected officials and business leaders visiting the USSR were often asked to share their observations following their return.

The documents show that RFK was a voluntary informant. In a statement Thursday, the CIA showed the meetings reflected RFK’s “patriotic commitment” to serving his country.

Many of his observations reflected granular observations about daily life.

“On 29 Aug 55, while in Novosibirsk, USSR, a friend and I visited a State machine factory. The factory has 3,500 employees, of whom one third are women. The wage scale is between 840 and 2,500 rubles,” Kennedy told the CIA interviewer, according to the documents. “The Director of the plant whose name I do not recall was frosty, although the engineer was friendly.”

The CIA used artificial intelligence to scan its library for documents related to RFK’s assassination that could be declassified. The search turned up many documents that had little to do with his killing, such as the records of RFK’s meeting with the CIA.

Kennedy’s son, U.S. Health and Human Services Secretary Robert F. Kennedy Jr., said he was gratified to see the documents’ release.

“Lifting the veil on the RFK papers is a necessary step toward restoring trust in American government,” Kennedy said.

The documents released Thursday included a September 1975 memo from then-CIA Director William Colby to staff, discussing allegations of CIA involvement in JFK’s assassination in Dallas on Nov. 22, 1963, that “have crept up every so often.” Colby asserted that JFK assassin Lee Harvey Oswald had no contact with the agency.

Colby said five pre-assassination CIA records did reference Oswald but “Oswald’s name had no particular meaning before that fateful event.”

Associated Press writer John Hanna in Topeka, Kansas, also contributed reporting.

The documents can be found online at cia.gov and archives.gov/rfk.