Chelsea and Bill Clinton in New York. Justin Sullivan/Getty Images) A former Secret Service agent who played a key role during the investigation into President Bill Clinton's affair with then White House intern Monica Lewinsky is already delighting conservative audiences with a searing tell-all book about the Clinton White House.

But on the heels of the Tuesday release of "Crisis of Character," author Gary Byrne is having a hard time explaining some serious discrepancies in his account, which has become a top best-seller on Amazon as presumptive Democratic nominee Hillary Clinton mounts a bid for the White House.

Last week, BuzzFeed reported that Byrne's claim that he destroyed towels allegedly stained with semen and lipstick directly contradicted testimony the former agent gave in 1998 as part of an investigation conducted by Kenneth Starr into the affair.

In a deposition, Byrne said he didn't ever see any such towels. He said he only heard White House steward Bayani Nelvis complain about having to clean up towels that Byrne assumed were the result of a physical relationship between Lewinsky and Clinton.

In an interview with Business Insider on Monday, Byrne insisted that there was no discrepancy between his accounts.

Official White House photo taken Nov. 17, 1995 from page 3179 of Independent Counsel Kenneth Starr's report on President Clinton, showing President Clinton and Monica Lewinsky at the White House. The White House/AP The former agent said that because he was instructed to only answer investigators' questions in the 1998 testimony directly and literally, they missed an opportunity to press him for the truth. Byrne claimed that investigators only asked him about semen-stained tissues, not hand towels.

"It's two different things that happened. One was lipstick on hand towels and some other stuff, and then one was tissues. They kept talking about tissues, tissues, tissues. It's not my job — I'm under oath, I have to tell the truth — but it's not my job to put them on the right path, to skewer the president. I didn't want to tell these investigators anything," Byrne said.

Pressed to clarify, he added: "They were hand towels. [The investigators] were asking about tissues. I was familiar with what they were talking about, but again, it's not my job to steer them straight."

But a closer examination of Byrne's testimony revealed more disparities.

During multiple depositions in the summer and fall of 1998 reviewed by Business Insider, Byrne said Nelvis was carrying "tissues or towels" when he and Byrne crossed paths in the White House. Byrne used both towels and tissues interchangeably when questioned by investigators in June 1998 and during a grand jury deposition on July 17, 1998.

From his testimony on June 25, 1998:

"He either had tissues or a towel, I don't remember which. And he said something, that he was tired of cleaning up this crap and this wasn't right or something to that effect. I don't remember if he said it to me — he must have said it to me because I don't remember seeing it, but I got the impression that there was lipstick on these towels. And I believe they were towels because he said something about putting them in the wash.

"And I said, 'Well Nel, who is going to see that?' And he said, 'Yeah, you're right.' And I said, 'Maybe it's best if you just, you know, get rid of it or whatever.'

"He had a plastic bag in his hand and I think it was like out of the trash bag. And then once again this was one of these uncomfortable things. I mean now, of course, and at the time. I, you know, basically, we left it at that and I turned around and walked out."

Byrne claimed during multiple depositions that he did not remember seeing the lipstick on the towels or tissues, and said he did not remember whether he had one conversation or multiple with Nelvis about them. Byrne also initially said he believed the lipstick belonged to a separate White House staffer but later claimed he assumed the lipstick was Lewinsky's, citing his "bad memory" for the mix-up.

Despite suggestions that he did not attempt to steer investigators, Byrne also was fairly forthcoming with some details of the lipstick exchange. When asked on June 25, 1998, whether he saw tissues or towels, Byrne clarified that they were white terrycloth, but he added that he could not recall seeing stains on them.

By the time Byrne wrote his book, his story had changed dramatically.

The book describes in vivid detail his destruction of the towels:

"Any boy lucky enough to live past his high school years could identify the stains, translucent and white, half gooey, and already absorbing into the fabric.

"I placed the offending linens in the trash bag and hid them in a furniture drawer near my post. I didn't let that drawer out of my sight until my very long day was done. Getting the trash bag to my gym bag to my car involved some risky moments, but I made it. In D.C. traffic I worried, Have I just illegally destroyed evidence?"

Byrne told Business Insider that he did not talk to any former Secret Service agents while writing the book, instead relying on his memory.

He also questioned BuzzFeed's motives for pointing out the discrepancy, saying the outlet was "deliberately trying to discredit" him. He also alleged that mainstream media outlets were attempting to silence him by not booking him for appearances on their shows.

"Obviously this guy writing this story is a Clinton supporter," Byrne said of the BuzzFeed author. "He's part of the problem. He wants to keep this story going — that she's this fictitious great leader, and she's not, she's not a leader. Not even a great follower."

Byrne did not respond to requests for clarification on Tuesday from Business Insider.

For its part, the Secret Service has distanced itself from Byrne.

In a rare statement last week, the Association of Former Agents of the US Secret Service questioned Byrne's credibility.

"One must question the veracity and content of any book which implies that its author played such an integral part of so many [claimed] incidents. Any critique of management by one who has never managed personnel or programs resounds hollow. Additionally, why would an employee wait in excess of ten years after terminating his employment with the Service to make his allegations public?" the statement said, according to Politico.