A leader in the investigation by the Department of Homeland Security into the Secret Service's 2012 prostitution scandal resigned after being implicated in a scandal of his own involving a prostitute.

David Nieland, the head investigator, quietly resigned in August after he was observed by Florida police entering and leaving a building held under surveillance in a prostitution investigation.

According to sheriff' deputies in Broward County, Florida, a prostitute interviewed as part of the inquiry identified Nieland in a photograph and said he paid her for sex.

Nieland's resignation came after he refused to answer the Department of Homeland Security's questions about the incident.

A spokesperson from the Department of Homeland Security's inspector general confirmed in a recent statement that Nieland did resign last August, but couldn't release many other details. He did add that officials in his department "became aware in early May of this year of an incident in Florida that involved one of our employees."

"While the law prohibits us from commenting on specific cases, we do not tolerate misconduct on the part of our employees and take such allegations very seriously," the spokesman, William O. Hillburg, said. "When we receive information of such misconduct, we will investigate thoroughly, and, during the course of or at the conclusion of such an investigation, we have a range of options available to us, including administrative suspension and termination."

In an email sent Tuesday, Nieland told the The New York Times that "the allegation is not true," but refused to answer any other questions.

Nieland was leading the internal investigation to determine whether the Obama administration attempted to cover up what went on before the Secret Service fired eight agents on assignment in Cartagena, Colombia during a presidential visit in April 2012. It was discovered that the agents had prostitutes in their hotel rooms during the trip.