Washington (CNN) - Secret Service Director Mark Sullivan is telling lawmakers he expects more resignations in the wake of the alleged prostitution scandal, with one congressional source saying additional agents will likely go by the end of the week, and a top Democrat is expressing concern that the Colombia incident could compromise the president's safety in the future.
Rep. Elijah Cummings, the ranking Democrat on the House Government and Oversight Committee, told CNN Thursday Sullivan told him he has "no doubt" all Secret Service agents involved in the prostitution scandal will resign, if the investigation makes clear their wrongdoing.
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"I said is it possible that these men would resign," Cummings told CNN, recounting his conversation with Sullivan. "He said he had no doubt that they would, that they probably would if, you know, the facts were found to be true. Why? Because of the culture. They have this pride – they don't want any bad apples, so they probably will leave."
Wednesday night three of the 11 Secret Service members involved were forced out.
Cummings said it is still not clear if the Columbia incident posed a security threat on that particular trip, but he expressed deep concern that the publicity surrounding it could compromise security in the future.
"The Secret Service is organization I put on level of Navy Seals. The elite. The very, very best in the world, and I don't want anyone to think they can pierce the armor of the Secret Service. I dont even want them to think it, i think its our duty, all of us in the Congress to make sure that the Secret Service is an organization we believe it to be," said Cummings.
Cummings, a senior African American lawmaker, also said there was already special concern for President Barack Obama, which he even hears from his constituents.
"People actually worry about that. They worry about it, and people have said to me, look, Cummings, if they would try to kill Reagan, I know they'll try to do some harm to this president. I hear that all the time," said Cummings.
When asked if that worry is because the president is African American, Cummings simply responded "I'm just telling you, that's what they ask me."
He did not say he has any specific, official information about threats to the president.
Cummings said he has the "utmost confidence in Sullivan" and does not think he needs to go, as at least one of his colleagues has said.
Cummings also said he is comfortable with the Secret Service doing the bulk of the investigating right now, and is happy with the decision to create an external board to review the agency's standards.
"I think their investigation will be extremely thorough, and that information needs to get out to the public. I don't want anybody who's imagining– imagining bringing some type of harm to the president or vice president and others being guarded by the Secret Service. I don't want them to even imagine that they can touch them," said Cummings.
Still, he is demanding answers.
On Wednesday, he and House Government and Oversight Chairman Rep. Darrell Issa wrote a sharply worded joint letter asking for the Secret Service to respond to a series of questions about the incident in Colombia, giving the agency a May 1 deadline.
Cummings said after they receive that information the committee will determine whether public hearings are necessary.