That’s the takeaway from a damningWashington Post report which finds that, according to both documentary and interview evidence, "senior White House aides were given information at the time suggesting that a prostitute was an overnight guest in the hotel room of a presidential advance-team member — yet that information was never thoroughly investigated or publicly acknowledged."
The story here revolves around a 2012 incident in which Secret Service agents were accused of drinking to excess and hiring a prostitute during a trip to Cartegena, Columbia, in preparation for a trip to the city by President Obama. Ten Secret Service agents were eventually fired in the scandal, but the White House publicly insisted that no administration staffer was involved.
Former White House press secretary Jay Carney, for example, said in April 2012 that "there have been no specific, credible allegations of misconduct by anyone on the White House advance team or the White House staff," and that after, a review, the White House’s council’s office said that no member of the advance team was involved in "improper" behavior.
On the contrary, according to the Post, another investigation within the Department of Homeland Security’s inspector general’s office found evidence suggesting that a White House advance team member was, in fact, involved. An investigator on the case contends that the evidence to that effect was suppressed:
The lead investigator later told Senate staffers that he felt pressure from his superiors in the office of Charles K. Edwards, who was then the acting inspector general, to withhold evidence — and that, in the heat of an election year, decisions were being made with political considerations in mind.
"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 DHS inspector general’s office, told Senate staffers, according to three people with knowledge of his statement.
Nieland added that his superiors told him "to withhold and alter certain information in the report of investigation because it was potentially embarrassing to the administration."
 The Post reports that those in the IG’s office who wanted to pursue questions about White House involvement were dealt with:
Within the inspector general’s office, investigators and their bosses fought heatedly with each other over whether to pursue White House team members’ possible involvement. Office staffers who raised questions about a White House role said they were put on administrative leave as a punishment for doing so. 
Not surprisingly, the Secret Service wasn’t—and apparently still isn’t—pleased with the fact that the White House failed to look into the behavior of its own team members even while many agents were being fired.
Adding to the intrigue is that the advance team member who may have been involved in the incident (his lawyer denies it) was a 25-year-old son of a lobbyist and Obama donor who also ended up working for the administration on the implementation health care law. Back to the Post: 
Whether the White House volunteer, Jonathan Dach, was involved in wrongdoing in Cartagena, Colombia, remains unclear. Dach, then a 25-year-old Yale University law student, declined to be interviewed, but through his attorney he denied hiring a prostitute or bringing anyone to his hotel room. Dach has long made the same denials to White House officials.
Dach this year started working full time in the Obama administration on a federal contract as a policy adviser in the Office on Global Women’s Issues at the State Department.
Dach’s father, Leslie Dach, is a prominent Democratic donor who gave $23,900 to the party in 2008 to help elect Obama. In his previous job as a top lobbyist for Wal-Mart, he partnered with the White House on high-profile projects, including Michelle Obama’s "Let’s Move!" campaign.
He, too, joined the Obama administration this year. In July, he was named a senior counselor with the Department of Health and Human Services, where part of his responsibilities include handling the next phase of the Affordable Care Act.
The details are complex, and the actual "misconduct"—hiring a prostitute in Colombia, where it’s legal to do so—is perhaps politically embarrassing but hardly misconduct at all, and certainly not the sort of thing likely to swing a not-very-close national election. And yet the administration apparently chose to delay findings and mislead the press about what happened anyway. 
So the short version is this: The administration had evidence indicating that a young advance team member, who was also the child of a lobbyist-and-donor-turned-administration-staffer, was involved in a potentially embarrassing incident with a prostitute while serving as a member of the presidential advance team—and yet explicitly denied that this was the case, and also appears to have pressured independent investigators to delay and withhold evidence until after the election was over.
And the question the story raises is: If the White House was so determined to cover up this embarassing but relatively minor incident, what larger stories has the White House suppressed or covered up that we don't know about?