Frank Olson and Kurt Blome (who had become a protegé of the Americans) later met at Camp King in Germany in the early 1950s when Olson made several visits there to participate in "Operation Artichoke", in which the U.S. Army and the CIA experimented with the use of drugs (including LSD) in interrogation. Olson was present during brutal interrogations by the Americans of Soviet prisoners and suspected double agents, some of whom died under torture.
Olson was deeply disturbed by what he had seen.
...
In November 1953 Olson attended a meeting of a group of CIA agents at a country retreat where they discussed their work. Olson was suspected by the CIA of being a security risk. He was given a drink laced with LSD and when well under the influence of the drug he was subjected to interrogation using Artichoke techniques, probably a very unpleasant experience.
A week later Olson was staying in Room 1018A at the Hotel Statler in New York City under the supervision of a CIA doctor, Richard Lashbrook. The manager of the hotel, Armond Pastore, heard a thump outside and went out to find Olson dying on the pavement, having fallen from the 13th floor. The manager later found that a phone call had been made from Room 1018A to a number in Long Island and the caller had said only, "Olson's gone."
The CIA maintained that Olson had leapt through the closed window to his death. However, an autopsy conducted forty years later on the exhumed corpse revealed an injury to the skull most likely caused by a blow to the head and no evidence of any cuts to the body from broken glass. It seems that Olson, exactly as recommended in a CIA assassination manual, was struck on the head (possibly while drugged) and thrown from the window to his death thirteen floors below.
http://www.serendipity.li/cia/olson2.htm Statement from the Olson family, 2002:
1. The death of Frank Olson on November 28, 1953 was a murder, not a suicide.
2. This is not an LSD drug-experiment story, as it was represented in 1975. This is a biological warfare story. Frank Olson did not die because he was an experimental guinea pig who experienced a "bad trip."
He died because of concern that he would divulge information concerning a highly classified CIA interrogation program called "ARTICHOKE" in the early 1950's, and concerning the use of biological weapons by the United States in the Korean War.
3. The truth concerning the death of Frank Olson was concealed from the Olson family as well as from the public in 1953. In 1975 a cover story regarding Frank Olson's death was disseminated. At the same time a renewed coverup of the truth concerning this story was being carried out at the highest levels of government, including the White House.
The new coverup involved the participation of persons serving in the current Administration.
http://www.frankolsonproject.org/Statements/FamilyStatement2002.html