Ilya Mamantov was born in Russia in 1914. When he was seven years old his family moved to Latvia. He later studied geology at the University of Latvia. In 1938 he married Dorothy Gravitis and continued to live in Riga during the Second World War.
Mamantov emigrated to the United States and in 1951 he found work as a production scheduler at the Lion Match Company in New York City. The following year he was employed as a seismologist by the Donnally Geophysical Company in Dallas.
Mamantov also worked in Roswell, New Mexico, Snyder, Texas and Forest, Mississippi, before being employed by the Sun Oil Company in September 1955. He now returned to Dallas where he purchased a home at 6911 East Mockingbird. Around this time he got to know Jack Alston Crichton.
Mamantov became a member of the Republican Party, according to Russ Baker, the author of Family of Secrets, he was "a vociferous anti-Communist who frequently lectured in Dallas on the dangers of the Red menace." George Michael Evica argues that "Mamantov and Crichton shared a right-wing orientation centered in the Republican Party".
On 22nd November 1963, President John F. Kennedy, was assassinated in Dallas. Jack Alston Crichton arranged for Mamantov to work for the Dallas Police Department as a translator for Russian-born Marina Oswald. He translated for Oswald during her initial questioning by the Dallas authorities in the hours immediately after her husband Lee Harvey Oswald had been arrested.
Walt Brown argues in Treachery in Dallas (1995) that Mamantov was "contracted to serve as translator by Jack Crichton of army intelligence and was then called a second time in quick order by the police, and subsequently picked up and driven to police headquarters in a Dallas police squad car, strongly suggestive of a police-intelligence linkup."
Russ Baker claims that these "were far from literal translations of her Russian words and had the effect of implicating her husband in Kennedy's death."George Michael Evicaargues in A Certain Arrogance (2006) that Mamantov knew James Herbert Martin, an associate of Jack Ruby.
Mr. MAMANTOV. No; we got to Seminole--one more place I went from there. No; two more places--I went from Seminole to Snyder, Tex., and from Snyder, Tex., I went for 3 weeks to Forest, Miss., and at that time I quit the company and got my job with Sun Oil Co. here in Dallas.
Mr. JENNER With Sun?
Mr. MAMANTOV. Right; and purchased our home at 6911 East Mockingbird in October, the 1st of October 1955.
Mr. JENNER. Now, what is your facility in the command of the Russian language, with particular reference to--did you or have you done any teaching of the language?
Mr. MAMANTOV. Yes; I am teaching since 1960 here in the Dallas area. I taught scientific research to some men, of a research personnel in 1960-1961. And, I taught in the Austin College in Sherman from--it was the fall of, yes, it was fall of 1961 and 1962 No--1962 and 1963. Now, I am teaching at SMU or Dallas College, to be specific, of SMU.
Mr. JENNER. Have you done any interpreting or translating?
Mr. MAMANTOV. Yes, sir; for the American Geophysical Union, quite extensively in 1959, 1960, and 1961, and I think--yes--1961 I finished.
Mr. JENNER. And have you also done any interpreting or translating for any law enforcement agencies?
Mr. MAMANTOV. Here in the States?
Mr. JENNER. Yes.
Mr. MAMANTOV. Let me think a little--no, I don't remember. I have translated minor papers, you see, like Soviet Union's marriage certificates and birth certificates for our local courts connected with divorces, and I might be of a help to a group of Latvians, people here in town, when they received their citizenship, so much, but this is the first time for the police department.
Mr. JENNER. All right. I'll get to that. Have you ever been called upon by either any agency of the Government of the United States or of the State of Texas or the City of Dallas to do any interpreting or translating?
Mr. MAMANTOV. Yes, I was called by the police force for the City of Dallas around 5 o'clock, November 22.
Mr. JENNER. What year?
Mr. MAMANTOV. Of 1955, on 2 or 3 minutes' notice.
Mr. JENNER. It was 1955 or 1963?
Mr. MAMANTOV. Excuse me, 1963.
Mr. JENNER. I got from what you have said, then, you had no prior notice?
Mr. MAMANTOV. No; sir.
Mr. JENNER. You were called by some official of the city police department?
Mr. MAMANTOV. Yes; I was called by Lt. Lumpkin. I think he's Lieutenant--they call him Chief.
Mr. JENNER. And you repaired then to the Dallas City Police Station?
Mr. MAMANTOV. Excuse me, I was called by somebody else, a couple of minutes ahead of Lumpkin--is it important?
Mr. JENNER. I don't know--you might state what it is.
Mr. MAMANTOV. All right. I was called by Mr. Jack Chrichton, C-h-r-i-c-h-t-o-n (spelling)--I don't know how to spell his name right now, but I guess it is that, but I can find out in a day or two.
Mr. JENNER. And who is he?
Mr. MAMANTOV. He is a petroleum independent operator, and if I'm not mistaken, he is connected with the Army Reserve, Intelligence Service. And, he asked me if I would translate for the police department and then immediately Mr. Lumpkin called me.
Five hours after the assassination, Ilya Mamantov, who had never met Oswald, received a phone call from Jack Crichton asking him to serve as "interpreter" for the first interrogation of Marina. Crichton was in 1963 the president of Nafco Oil & Gas, Inc., and a former Military Intelligence officer still connected with Army Reserve Intelligence. According to information uncovered by the Garrison investigation, Crichton had been among a small group of Army Intelligence officials who met with H. L. Hunt soon after the assassination.
Now it was Ilya Mamantov who, at the request of this Army Intelligence Reserve officer, went to the first post-assassination session with Marina. Also present was Marina's protector since April 1963, Ruth Paine. Marnantov was, curiously, the one member of the Russian community besides de Mohrenschildt who knew the allegedly ultra liberal Paine.
No transcript exists of Marina's first questioning by Mamantov, Paine, and the Dallas police. Her second interpreter on Sunday, November 24, was Peter Gregory. Right after the Oswalds' return from the USSR, Gregory, a petroleum engineer and Russian-language instructor, had been the first member of the Dallas-Fort Worth expatriate community whom Oswald met. Oswald had listed Gregory as a reference in obtaining his first job in the region, at Leslie Welding. Gregory's son Paul became the couple's first friend, having long discussions with Lee on political philosophy. But Peter Gregory had not seen Oswald since October 1962. Then he and his Secret Service agent friend Mike Howard came to spend the entire day of Oswald's death with Marina and Oswald's mother, Marguerite-under circumstances that were never adequately explained.
Researcher Peter Dale Scott, who studied the transcripts of Gregory's several translations with Marina, noticed numerous inconsistencies. Six days after the assassination, in the presence of Gregory and Russian-speaking Secret Serviceman Lee Gopadze, Marina contradicted her testimony of three earlier interviews. At first she had said she could not describe Lee's rifle, nor had she ever seen a gun with a telescopic sight. Then, on November 28, Marina allowed that she could recognize the rifle without question and admitted taking the famous photograph of Oswald holding the weapon, including the scope that she had allegedly never seen. On December 3, Marina "revealed" that her late husband had also fired at General Walker-an allegation that the Munich newspaper had published a week earlier.
The Oswald women were sequestered at the time in an Arlington, Texas, motel, the Inn of the Six Flags. Its manager, James Herbert Martin, soon became Marina's business agent, even temporarily lodging her in his home early in 1964. It was Martin who negotiated the sale of the photograph of Oswald posing with his rifle and two left-wing newspapers, which appeared on the cover of Life magazine on February 21, 1964.
All of this convinced Scott, and other researchers, that Marina-barely able to speak English, terrified of being deported back to the LSSSR - was manipulated by her "handlers" to incriminate Oswald in the proper manner.