Gregory and Mark Lane conducted landmark research into the assassination of Dr. Martin Luther King Jr., helping move the U.S. House Select Assassinations Committee to investigate the murder, along with that of John F. Kennedy. Lane was the author of conspiracy theory books such as "Rush to Judgment". The pair wrote the King conspiracy book "Code Name Zorro", which postulated that convicted assassin James Earl Ray did not act alone. Gregory also argued that the moon landing was faked and the commonly accepted account of the 9/11 attacks is incorrect, among other conspiracy theories.