When several magazines and journalists, including Newsweek and Keith Olbermann, attempted to investigate the claims of the book and profile Anthony, they contacted the woman who claimed to be his adoptive mother, Vicki Johnson. Suspicion was raised when it was learned that no one other than Vicki Johnson had actually seen Anthony – not his agent, his editor, nor his publicist. Further concerns were raised, when a voice analysis expert analyzed calls from "Anthony" and identified the voice to be that of Vicki Johnson.

As a result of these irregularities, Olbermann hired a special investigator who suggested that there was no Anthony and the story was fabricated.

A Rock and a Hard Place claimed that Anthony's biological parents were arrested and tried for abusing him, and that his police officer father was killed in prison. An alleged conspiracy of rogue police officers trying to kill Anthony was Vicki Johnson's justification for zealously preserving Anthony's privacy. However, no case matching that description could be found at any social service agency.

Many sources find it medically implausible that Anthony could be alive, given that he has supposedly been living with AIDS for over 19 years. Most long-term survivors are actually living with HIV but had not yet developed full-blown AIDS; furthermore the medications that slow the progress of the disease were not known at the time that Anthony's AIDS allegedly became severe.

With so many similarities between the purported life of Anthony and proven hoaxes such as that of Kaycee Nicole and Kodee Kennings, the prevailing belief is that Anthony never existed.

Paul Monette wrote a foreword for an edition of A Rock and a Hard Place, later defending the book's veracity. Armistead Maupin, who wrote a blurb for an edition of A Rock and a Hard Place, later wrote The Night Listener, a novel subsequently made into a film, in which the main character begins correspondence with an HIV-positive boy who is not what he seems. The book parallels Maupin's experience with Johnson. The story also was adapted for a 2002 episode of Criminal Intent entitled "Faith", with the child's sex being changed to female and illness to amyotrophic lateral sclerosis.

On January 12, 2007, the ABC newsmagazine program 20/20 revealed new evidence that Anthony was Vicki Johnson's fictional creation. The photo of "Anthony" that Vicki had sent to Anthony's supporters was revealed to be a childhood photo of Steve Tarabokija, now a healthy adult and a New Jersey traffic engineer, who was shocked to find his photo being represented to people as the face of Anthony Godby Johnson. One of the viewers who recognized the photo was a woman whose son had been in the same fourth-grade class as Tarabokija. Their teacher for that class was Vicki Johnson, who had been said to have taken pictures of the children in the class.

Vicki Johnson, whose real name was Joanne Vicki Fraginals, had allegedly handed Anthony over to another caretaker in 1997 when she moved to Chicago and married Marc Zackheim, a child psychologist and owner of the Associates of Clinical Psychology. In 2004, Zackheim was indicted for abusing child patients at a treatment center for troubled children in Indiana; his trial began in 2006 at the Marshall County courthouse. He was acquitted of one felony count of practicing medicine without a license and three misdemeanor counts of battery for inappropriately touching boys. He died of a heart attack in 2009.