WASHINGTON– The investigation into the Colombian prostitution scandal that rocked the Secret Service two years ago was tampered with for political reasons, according to a new report.

The lead investigator into the embarrassing drunken sex scandal told Senate staffers that his superiors asked him to withhold evidence and stall the report until after the presidential election.

“We were directed at the time . . . to delay the report of the investigation until after the 2012 election,” David Nieland, the lead investigator on the Colombia case for the homeland security agency, told Senate staffers according to the Washington Post.

A White House spokesman insisted there was no interference in the investigation by the president or his team.

Neiland said he was under heavy pressure from his superiors who told him “to withhold and alter certain information in the report of investigation because it was potentially embarrassing to the administration.”

The Obama administration repeatedly denied that any member of the White House team was part of the drunken sex scandal during an April 2012 presidential trip to Cartegena, but the Washington Post also reports that records show one Obama advance-team member had a prostitute registered to his hotel room as well.

Nearly two dozen Secret Service and military personnel tasked with presidential protection were disciplined for the embarrassing partying, but there was no reprimand for the White House aide, Jonathan Dach, then a 25-year-old Yale law school student who volunteered for the trip. He has denied any involvement.

Dach and his father, a deep-pocketed Democratic donor, are currently Obama administration employees. Jonathan Dach is a policy adviser at the State Department. Leslie Dach is a senior counselor with the Department of Health and Human Services, where he’s working on Obamacare implementation.

The Obama administration insists there was no credible evidence that anyone was involved from the White House. The White House was informed of Dach’s involvement, but presidential aides conducting an investigation concluded he had done nothing wrong.

The developments are the latest black eye in the ongoing Secret Service scandal.

Director Julia Pierson resigned last week following shocking revelations of security lapses. First a knife-carrying Army veteran hopped the White House fence Sept. 19 and ran into the unlocked mansion before an off-duty agent tackled him. Then the Washington Post disclosed the White House was shot-up in Nov. 11, 2011, but it took four days for agents to realize what happened when a house keeper found the broken window.

The final straw on Pierson’s tenure came when it was revealed Obama entered an elevator with an armed man during his Sept. 16 trip to Atlanta — and the White House wasn’t notified until the news was breaking.