(CBS News) Ronald Kessler, best-selling author of "In the President's Service" and a former reporter for The Washington Post, called the dismissal of 12 Secret Service members in Colombia prior to President Obama's arrival there "the biggest scandal in Secret Service history."
A source in the Secret Service told CBS News that one or more of the officers was involved with prostitutes and that there was a dispute over payment. One prostitute went to the police, who notified the State Department.
According to sources two of the Secret Service personnel sent home were supervisors; the rest were part of a detail assigned to logistics. None of those relieved of duty was a member of the president's protective detail.
On "CBS This Morning: Saturday," Kessler said the Secret Service has a culture of corner-cutting.
"They don't have enough agents, they don't even put people through metal detectors sometimes because there's pressure to let everybody in," Kessler said. "It's like letting passengers in an airplane without putting them through metal detectors. They don't keep up-to-date with the latest firearms. They don't even do physical tests. So, it's a culture that leads to this kind of problem."
Kessler pointed to a couple crashing a White House state dinner without an invitation as an example of a potential security threat.
He said that Mark Sullivan, director of the Secret Service, should have been fired after the fiasco involving gate-crashers Michaele and Tareq Salahi, but has continued in the same position because of President Barack Obama's confidence in the agency.
"President Obama keeps saying, 'I have full confidence in the Secret Service,'" Kessler said. "You know, he deals with agents who are very admirable, so he thinks, 'Well, the Secret Service must be fine.' But, you know, in my book...I go into dozens and dozens of examples of poor management.
"For example, when [Dick Cheney's daughter] Mary Cheney was under protection, she wanted her agents to take her friends to restaurants. Well, they're not taxi drivers. They are law enforcement officers, they refused, as they should have, but because of that she got her detail leader removed.
"So the Secret Service management didn't back the guy who is doing his job. And that kind of culture is the sort that leads to this kind of incident, where there's poor morale, there's hostility toward management."
Kessler called this latest incident in Colombia "a very shocking scandal."
He added the situation may be a sign of a trend because it involved supervisors. Kessler called it "just unbelievable" and a "tremendous embarrassment to the U.S."
He said that the Secret Service personnel's liaising with prostitutes could expose them blackmail to acquire access to secure areas. "They could have led to an assassination. And if you have an assassination, you nullify democracy. That's how important the Secret Service is."
Kessler went so far as to say the president's safety is in jeopardy because the replacements didn't have time to get acclimated to the situation.
For more with Kessler, watch the video in the player above.