One year after a dozen Secret Service agents were removed from their positions after a prostitution scandal, two senior supervisors for the agency face allegations of sending sexually oriented text messages to a female colleague. NBC's Kristen Welker reports.

A year after a prostitution scandal rocked the Secret Service, the agency is dealing with a new embarrassment after a senior supervisor was removed from his position for trying to retrieve a bullet he left in a woman's hotel room, a source told NBC News.

Ignacio Zamora oversaw two dozen agents in the president's security detail before the incident at Washington's luxury Hay-Adams Hotel in May, according to the Washington Post.

An investigation into Zamora's conduct at the hotel revealed that he and another supervisor, Timothy Barraclough, had sent sexually suggestive emails to a female subordinate, the newspaper reported.

A Secret Service official confirmed to NBC News that the agency opened an investigation in October into emails and texts from two agents after the agency was contacted by the newspaper.

Barraclough has been reassigned within the detail, a source familiar with the matter told NBC News.

"We have always maintained that the Secret Service has a professional and dedicated work force," Secret Service spokesman Ed Donovan said in a statement. "Periodically we have isolated incidents of misconduct, just like every organization does."

He added: "When these incidents occur, we work diligently to resolve them appropriately and quickly."

The agents did not return calls.

Rep. Mike McCaul, chairman of the House Committee on Homeland Security, told NBC News that a congressional review was under way.

"Recent reports of inappropriate behavior within the Secret Service are unacceptable and the committee is looking into the matter," he said.

"Allegations of misconduct on the part of those tasked with protecting the nation's highest officials are extremely concerning. The integrity of those looking after our First Family must be exemplary, and anything less does our entire nation a disservice."

A source familiar with the matter told NBC News that Zamora was off-duty when he met a woman at the hotel, which overlooks the White House. After he left, he realized he had left a bullet in her room and went back to the hotel and asked the front desk if he could retrieve it, the source said.

The Post reported that the agent tried to get into the woman's room to retrieve the bullet and she would not open the door. A report of the incident led to Zamora being punished internally.

The Hay-Adams incident happened a year after eight Secret Service agents lost their jobs amid allegations they brought prostitutes back to their rooms while preparing for a summit in Cartagena, Colombia.

In a letter sent to Charles Edwards, deputy inspector of the Department of Homeland Security, two members of Congress said Zamora’s behavior as described by the Post was “especially alarming” since people described as “confidential whistleblowers” told them that Zamora had gone to Colombia to investigate the sexual misconduct in Cartagena.

“If true, these allegations raise serious questions both about the integrity of the Secret Service’s investigation and the culture of the agency,” the letter, signed by Sen. Ron Johnson, R-Wis., and Rep Jason Chaffetz, R-Utah, states.

The letter obtained by NBC News also requests a status update on an inspector general’s review of the Secret Service’s culture, promised a year and a half ago.

Reached by telephone, Secret Service spokesman Max Milien said the agency had no comment on the contents of the letter or the allegation that Zamora had also investigated Cartagena.

NBC News' Tracy Connor and Jeff Black contributed to this report.

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