WASHINGTON — An internal review found no evidence that White House staff members engaged in “improper conduct” in Cartagena, Colombia, White House spokesman Jay Carney said, but he confirmed that a member of a military communications team that supports the White House is under investigation for partying with prostitutes before the president’s visit earlier this month.

Carney said the Office of White House Counsel conducted the review of White House staff members “out of due diligence” and not in response to a “specific credible allegation.”

The Colombian prostitution scandal has consumed much of Washington for more than a week and led to rampant speculation, as reports of heavy drinking and hard partying among a Secret Service and military advance team have leaked out.

“There is no indication that the White House advance team engaged in any improper conduct or behavior,” Carney said.

An employee of the White House Communication Agency, however, is under investigation, Carney confirmed. The agency, known as WHCA, is a military unit that provides technical support for presidential travel. It works closely with White House staff but reports to the Defense Department.

The agency is the third to become ensnared in the controversy. A dozen Secret Service agents and 11 military service members are suspected of cavorting with 21 prostitutes in the days before the president arrived in Colombia for the Summit of the Americas on May 13. Six of the agents have lost their jobs, one has been cleared and five remain on leave. The Pentagon investigation is still under way.

Carney tried to distance the White House from the WHCA, whose employees are not hired or overseen by White House staff.

“It is a defense logistics agency,” Carney said. “They are no more members of the White House staff than Secret Service personnel who you see every day on the grounds here are members of the White House staff.”

A WHCA website describes the unit as seeking out “the best of the best” from all branches of the military.

“The opportunities for travel abound, and nowhere else in the Department of Defense are the challenges and responsibilities greater,” it reads.

Carney said the review of the White House staff occurred last week, but would not discuss details. He complained that it was prompted in part because of rumors circulating on websites “with no editors and no conscience.”

Secretary Leon Panetta says the Defense Department has suspended the security clearance of military members under investigation for possible roles in the Secret Service sex scandal that took place in Colombia earlier this month, The Associated Press reported.

Panetta told reporters Monday about the disciplinary action against the service members first embroiled in the scandal en route to Colombia, where he was making a long-scheduled visit to meet with defense officials there. It was not clear how many of the service members had security clearances.

“My biggest concern is the issue of security and what could possibly have been jeopardized by virtue of this kind of behavior,” Panetta said.