During the trial of Clay Shaw, he was questioned by New Orleans District Attorney Jim Garrison regarding his Warren Commission testimony in which he had mentioned a man named Clay Bertrand having called him shortly after the assassination of John F. Kennedy asking him to represent Lee Harvey Oswald in Dallas, Texas.

In August, 1967 Andrews was convicted on three counts of perjury for lying to a grand jury in his previous testimony.

On November 25, 1963, Andrews informed the Federal Bureau of Investigation (FBI) that three days earlier (on the day of the assassination of President Kennedy) he received a telephone call from a Clay Bertrand who asked him whether he would be willing to represent Lee Harvey Oswald, the accused assassin.

[9][10] Garrison further believed that Shaw and a group of right-wing activists, including David Ferrie and Guy Banister, were involved in a conspiracy with elements of the Central Intelligence Agency (CIA) in the Kennedy assassination.

Andrews contradicted his testimony before the Warren Commission when, after appearing before the Orleans Parish grand jury, he stated in an interview on June 28, 1967 that Bertrand was not Shaw but was Eugene Davis, his friend and client.