A defense attorney for Joaquín "El Chapo" Guzmán said the Mexican drug lord received an unfair trial, claiming there were "plenty of errors" during the nearly three months of testimony in which multiple witnesses detailed the kingpin's rise to the head of the powerful Sinaloa Cartel.

"One of the witnesses believed that the Earth was about to be destroyed in an apocalypse. He believed in 15-foot aliens roaming the Earth searching for gold. And I wasn't allowed to question him on any of that. So the jury perhaps believed that he was sane when, in fact, it was pretty clear that he was out of his mind," attorney Jeff Lichtman told "CBS This Morning."

Guzmán was found guilty on all 10 counts Tuesday including drug trafficking and money laundering and is expected to be sentenced to life without parole in June. His attorneys said they plan to appeal the conviction.

"One of the cooperating witnesses was threatening the people in the government, threatening to show all details about the witness protection program to the Mexican cartels. We were not allowed to cross-examination on that," Lichtman said.

Lichtman, who has defended other high-profile clients including American mobster John "Junior" Gotti, said he was "restricted" from going into "very basic areas" of the case and said it was difficult to get around "the myth of El Chapo." He also said his team has never denied Guzman's involvement in drug dealing but instead disputes his role as the "kingpin" of the operation.

"That was the charge that landed him in prison for the rest of his life if he was convicted. So our position was, he was really a fall guy. There is a guy in Mexico who leads the Sinaloa Cartel who has been indicted in America for decades. He's been indicted in Mexico. He has never been arrested in 50 years," Lichtman said.

Last month, unsealed court documents revealed allegations not heard by the jury that Guzman had sex with girls as young as 13 and during the trial, one of his smugglers testified that one of Guzman's hitmen had a "murder room" in his mansion, complete with a sound-proofing and a drain in the floor for cleanup.

Following his conviction Tuesday, Lichtman said his client was "cool as a cucumber" upon hearing the verdict and a "pleasure" to represent.

"Listen, being a cool cat and a pleasure to represent does not make him a good person," Lichtman said when asked about Guzman's character. "He was good to me. And if I, as a defense lawyer, if I start being concerned with what people are accused of and what they're convicted of, I'll never be able to get out of the bed in the morning."

Asked if the jurors who convicted Guzman have anything to be concerned about he said, "Of course not. I don't think so," noting the near-complete isolation he's been in for two years.