No one alleged that an assassination team was arrested in Chicago. The Thomas Vallee incident was well documented (see: Final Report of the HSCA at p. 231). We do know that JFK cancelled his Nov. 2/63 trip to Chicago and that appears to be security related. Bolden was referring to an FBI telex that he said he read.
The problem with the Bolden case was the lack of independent corroboration for the evidence of Jones and Spagnoli. It would be the equivalent of charging Oswald with the murder of JFK solely on the basis of two people who were charged with murder saying that Oswald told them that he was going to try to assassinate JFK (with none of the other evidence against Oswald and Oswald having no connection to the TSBD).
Huh? Per the HSCA:
In addition [to the threat by Thomas Arthur Vallee], the committee obtained
the testimony of a former Secret Service agent, Abraham Bolden, who had been assigned to the Chicago office in 1963. He alleged that shortly before November 2, the FBI sent a teletype message to the Chicago Secret Service office stating that an attempt to assassinate the President would be made on November 2 by a four-man team using high-powered rifles, and that at least one member of the team had a Spanish-sounding name. Bolden claimed that while he did not personally participate in surveillance of the subjects, he learned about a surveillance of the four by monitoring Secret Service radio channels in his automobile and by observing one of the subjects being detained in his Chicago office.
According to Bolden's account, the Secret Service succeeded in locating and surveillance
two of the threat subjects who, when they discovered they were being watched,
were arrested and detained on the evening of November 1 in the Chicago Secret Service office.
The committee was unable to document the existence of the alleged assassination team. Specifically,
no agent who had been assigned to Chicago confirmed any aspect of Bolden's version. One agent did state there had been a threat in Chicago during that period, but he was unable to recall details. Bolden did not link Vallee to the supposed four-man assassination team, although he claimed to remember Vallee's name in connection with a 1963 Chicago case. He did not recognize Vallee's photograph when shown it by the committee.
